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UNITED STATES OF AMERICA. 



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The American Science Series. 

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ASTRONOMY. By Simon Newcomb, Supt. Ameri- 
can Nautical Almanac, and Edward S. Holden, 
Director of the Washburn Observatory. $1.40. 

THE HUMAN BODY. By H. Newell Martin, 
Professor in the Johns Hopkins University. $1.50. 

ZOOLOGY. By A. S. Packard, Jr., Professor of 
Zoology and Geology in Brown University, Editor 
of the American Naturalist, $1.40. 

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HENRY HOLT & CO., Publishers, 

NEW YORK. 



\^\^ 



AMERICAN SCIENCE SERIES, ELEMENTARY COURSE 



THE HUMAN BODY 



A BEGINNER'S TEXT-BOOK 

OF 

AJS^ATOMT, PHYSIOLOGY A^^D HYGIENE 



WITH DIRECTTOlSrS FO'R ILLUSTRATING IMPORTANT FACTS 

OF MAN'S ANATOMY FROM THAT OF THE LOWER 

ANIMALS, AND WITH SPECIAL REFERENCES TO 

THE EFFECTS OF ALCOHOLIC AND OTHER 

STIMULANTS, AND OF NARCOTICS 



,^' 



\ ./ BY 

H: NEWELL MAETIN, D.Sc, M.A., M.D. 
Professor of Biology in (he Johns Hopkiiu University 

AND 

HETTY CAEY MAETIN 



hS 







If 6 if J 



NEW YOUK 
HENEY HOLT AND COMPANY 

1884 



Q-? - 



^ 



Copyright, 1884, 

BY 

HENRY HOLT & CO. 



PREFACE. 



This little book is an attempt to express accurately 
and yet in simple language, those facts concerning the 
structure and actions of the living human body which 
it is desirable, for practical purposes, that every one 
should know. It is essentially a school-book of personal 
hygiene. Little, if any, more Anatomy and Physiology 
is introduced than is necessary to make clear the reasons, 
as regards the preservation of health, for following or 
avoiding certain courses of conduct. This, of course, 
includes all the broad facts of Human Anatomy and 
Physiology; but subjects of merely professional impor- 
tance or of purely scientific interest have been omitted. 
As regards Hygiene, attention is for the most part only 
directed to matters which are usually within the easy 
control of each individual. It seems useless to burden 
boys and girls with sanitary laws which need the aid of 
a physician or engineer for their successful application. 

A very earnest attempt has been made to present the 
subject so that children may easily understand it, and, 
wherever possible, to start from familiar facts and gradu- 
ally lead up to less obvious ones. In this part of the task, 
which was really the most difficult, I have had so much 
aid from my wife's experience in teaching young pupils, 
that her name properly has a place on the title-page. 



IV PREFACE, 

We both desire to express our obligations to Miss 
Frances T. Bauman, who placed freely at our disposal the 
results of her long and eminently successful experience 
in teaching Physiology to children. 

As appendices to certain of the chapters there are 
practical directions for the illustration of various facts 
in Anatomy and Physiology, which can be shown to pu- 
pils without any special apparatus, or any material not 
easily obtained. 

Particular attention has been given to the action on 
the body of the more commonly abused stimulants and 
narcotics, especially alcohol. 

H. Newell Martin. 

Johns Hopkins University, June 30, 1884. 



CONTENTS. 



CHAPTER PAGE 

I. The General Plan on which the Human Body is Built.. . i 

II. The Skeleton 12 

III. The Structure, Composition, and Hygiene of the Bones. 24 

IV. The Organs of Movement : Muscles and Joints 35 

V. Care of the Joints and Muscles 48 

VI. The Skin 59 

VII. Hygiene of the Skin. — Animal Heat. — Clothing. ...... 71 

VIII. Foods 81 

IX. Stimulants 91 

X. Digestion 98 

XL Digestion, concluded no 

XII. Hygiene of the Digestive Organs 123 

XIII. The Circulation 133 

XIV. Hygiene of the Circulatory Organs 153 

XV. Respiration 163 

XVI. Hygiene of the Respiratory Organs 176 

XVII. The Kidneys 185 

XVIII. The Nervous System 190 

XIX. Hygiene of the Nervous System 203 

XX. Narcotics 216 

XXI. The Sense Organs 223 

XXII. Summary concerning the Action of Alcohol on Body, 

Mind, and Character 240 

Glossary 247 

Index 255 



THE HUMAN BODY. 



CHAPTER I. 



THE GENERAL PLAN ON WHICH THE HUMAN BODY IS 

BUILT. 

1. Why we should Learn about our Bodies. — Suppose 
you had given to you a delicate instrument, such as a 
watch: you would desire to be told something of the way 
it was made, how it w^as to be used, and what was apt to 
harm it. Even a little knowledge of these things would 
help you to take better care of the watch. 

Now every one of us is responsible for the care of a 
body made up of many more parts than we find in a 
watch, and any of them liable to be injured in number- 
less different ways. If all the parts work well we are in 
healthy able to enjoy our lives, do our work, and aid those 
who are less fortunate. If we lose our health we not 
only can do less and enjoy less ourselves, but are likely 
to become a burden upon others. It is therefore one of 

T. If you have a watch, what ought you to know of it, and why? 
What is the nature of the machine given to every human being to 
take care of ? If it is kept in good order, what is the result ? If not ? 
What then is our duty with regard to it? 



2 ANATOMY AND PHYSIOLOGY, 

our first duties to learn enough about our bodies to be 
able to avoid doing things likely to harm them, or neg- 
lecting to do that which is for their welfare. 

2. What Anatomy is. — We could not look at the watch 
without seeing that it was made up of different pieces, as 
case, and face, and hands; and a glance at the works in- 
side would show us that dozens of parts, such as wheels, 
and pivots, and springs, and screws, without which the 
portions we see on the outside would be useless, were 
fixed together in a special way to make the watch. 

Likewise, on looking at the outside of the body you 
easily perceive head, and neck, and trunk, and arms, and 
legs; and if you could see into the inside you would find 
hundreds of other parts, which move the parts you see 
and make them useful. The science which teaches us 
the shape and size of all the parts of the body, where 
they are placed in it, and how they are joined together, 
is named Human Anatomy, 

3. What Physiology is. — On examining the parts of 
which a watch is made we find that each has its use: the 
case to protect the works, the glass to let us see the face 
and yet keep out dust, the hands to show the hour, th 
spring to keep it going, and so forth. 

In like way it is found that the various parts of the 
body have their uses: as the eyes to see, the mouth to 
eat, the legs to walk with. The science which teaches 
the uses of all the parts of the body, more particularly of 
its inner parts, is named Human Physiology, 

2. What do we easily find out on examining a watch? In this r'^- 
spect how may the body be compared to a watch? What is Humai. 
Anatomy ? 

3. Why are there many parts in ^ watch ? In the body ? What is 
Human Physiology ? 



HYGIENE. 3 

4. What Hygiene is. — Lastly, when you had learned 
something of how the watch was made and what each part 
of it had to do you would know that certain things must 
injure it; that it should be kept dry lest the steel springs 
rust, and that the case must be kept closed to prevent 
dust and grit from getting into the works. You might 
also be told some things which it would take you a 
longer time to find out for yourself; as, for example, that 
if the watch is to be a good time-keeper it must be regu- 
larly wound up, and not at one time one day and at 
another the next, or perhaps quite forgotten a third. 

So, without learning much Anatomy and Physiology 
you will readily see that certain things must be bad 
for your body: such as getting wounds that will cause 
great loss of blood, or going without food. The harm- 
fulness of other things it might take you a long time to 
find out by yourself; as, for example, that by breathing 
foul air or taking too little sleep, eating imprudently or 
drinking what is called *^ spirits," you might very easily 
injure your body beyond cure. Unless you were warned 
you would probably not discover the danger until too 
late to avert it. 

Just as a watchmaker could save you a great deal of 
time and risk by giving the results of his experience as 
to the best way to manage a watch, physicians and others 
who have made a study of what is good and what bad 
for the human body can save us much labor and danger 
by telling what they have found out. The science which 



4. Having examined a watch, what would at once occur to you about 
its preservation ? What studies teach you that certain %ings would 
be bad for your body ? Name some injurious habits that the ex- 
perience of others warns you to avoid. What is meant by Hygiene? 



4 ORGANS AND TISSUES. 

teaches what is good and what nurtful to our bodies — in 
other words, how we may best preserve our health — is 
known as Hygiene, 

5. Organs and Functions. — The separate parts of which 
the body is made up are called organs: thus the eye is the 
organ of sight, the teeth are organs of chewing, the stom- 
ach is an organ of digestion. The use of any organ is 
spoken of as its function : thus the function of the eye is 
seeing, of the ear hearing, of the hand grasping. 

6. The Structure of Organs. — The human body, like a 
watch, not only has numerous parts, but these parts are 
made of different materials. Taking the hand, for ex- 
ample, we observe on the outside, skin, nails, and hairs. 
If the skin were removed we should see below it some 
fat, just like that in beef and mutton. Under the fat, in 
the ball of the thumb you would find some red flesh, 
called muscle, which answers to the lean of meat. Be- 
neath all the rest would be white hard bones. At the 
finger-joints where the ends of separate bones come near 
together you would see covering each a thin layer of 
gristle or cartilage. And binding together the skin and 
fat and muscles and bones would be found a stringy sub- 
stance which, as it unites all the rest, is called the con- ^ 
nee live material. 

7. Tissues. — Each kind of material used in constructing 
the body is called a tissue: and each tissue has its own 
peculiar properties. Connective tissue is tough and suited 



5. What is an organ ? Give examples. What is a function ? Il- 
lustrate. 

6. What is meant by the structure of an organ ? Describe the 
structure of the hand. 

7. What is a tissue ? Name and describe some tissues. Name 
some liquids of the body. 



THE PLAN ON WHICH MAN'S BODY IS BUILT, 5 



to bind parts together. Bony 
tissue is stiff and useful to sup- 
port softer parts. Cartilage tis- 
sue is elastic and forms admir- 
able springy cushions between 
the hard bones. Muscle tissue 
has power to move parts to which 
it is joined; and so on. 

In addition to the solid tissues, 
liquids form part of the body: 
as the blood which we see flow 
from a cut finger, and the saliva 
which moistens the mouth. 

8. The General Plan on which 
the Body is Built. — If a man's 
body were sawed in two down 
the middle, so as to separate 
it into right and left halves, we 
should see something like Fig. i, 
if we looked at the cut surface 
of the right half. On examining 

the figure you see that there are Fig. i.— a section along the mid- 
die of head, neck, and trunk. <5, 

two chief cavities or chambers the chest, and c, the abdominal 

division of the ventral cavity sep- 

in the body, havins: between them crated by the diaphragm, d. a', 

-' ' ^ the enlarged upper end of the dor- 

the row of bones e e; these bones -! ^^^S'e Twt nfrrowe' pt^ 
together form the back-bone or °^i*1 ^°rT'^'"Jf rthe'pTtftio^ 

r^j.:..^ TU^ ^U«,^K^*. Z? /^ :.^ formed by the back-bone between 

Spine. Ihe chamber, B, C, m the ventral and dorsal cavities. /, 

r ^r^uuiu • 1- t^^ nose. 0, the mouth. /, the 

iront 01 the back- bone is much lungs; the tube leading down to 

. , . . , - them is the windpipe. ^, the 

the larger; it is named the zfen- heart, y, the stomach; the tube 

leading down to it is the gullet; 
tral cavity. The other chamber, the tube passing from the stomach 

to the lower end of the trunk is the 
a, a\ is the dorsal cavity. intestine. k, a kidney. s, the 

-^ sympathetic nervous system. 

8. How does the plan on which a watch is made compare with that 
on which the body is constructed ? In a human body cut down the 
middle what chief divisions would you find ? 




6 THORAX AND ABDOMEN. 

9. The Ventral Cavity, as you perceive in the fig- 
ure, does not reach up into the neck or head. It 
exists only in the trunk of the body, and is divided 
into an upper story, B^ the chest or thorax^ and a 
lower story, C, the abdomen^ by a partition, d^ which 
forms the floor of the thorax and the ceiling of the ab- 
domen. This partition is the diaphragin. How far in 
your own body the chest-cavity extends you can find out 
pretty accurately by beginning at the bottom of the neck 
and feeling down along the middle of the front of your 
trunk till you feel no more bones through the skin: 
that level marks the bottom of the thorax. 

10. Contents of the Thorax. — On Fig. i you will also see 
that the mouth, o^ and the nose, /, join behind, and that 
from the place of meeting two tubes run down the neck. 
The front one of these tubes is the windpipe or trachea; 
after entering the thorax it ends in the lungs^ I. In the 
thorax is also placed the hearty h. 

11. Contents of the Abdomen. — The second of the tubes 
above referred to is the gullet or oesophagus. It runs right 
on through the chest and diaphragm into the abdomen, 
and there opens into the stomachy f. 

The air we take in when breathing goes along the 
windpipe to the lungs, but no further: the food and 
drink which we swallow take a longer road along the 
gullet to the stomach. 

In addition to the stomach, the liver^ the intestines or 
bowels^ and the kidneys^ k^ lie in the abdomen. 

9. Where is the ventral cavity ? Name its divisions. The parti- 
tion. How can you trace the chest or thorax in your own body ? 

10. Name contents of thorax. 

11. What is the course of the gullet? Its use ? Use of the wind- 
pipe ? Name the organs which lie in the abdomen. 



CONTENTS OF THORAX AND ABDOMEN, 7 

12. What would be seen if the front of the Thorax and 
Abdomen were cut away. — This is represented in Fig. 2. 
Stretching across from side to side is seen the diaphragm, 




Fig. 2. — The trunk of the body opened from the front to expose the contents of 
the ventral cavity, zz, the diaphragm ; /«, lu\ the lungs ; h^ the heart ; ma^ the 
stomach; /«/, the spleen; ne^ ne, the membrane {great omentum) which lies in 
front of the intestines and kidneys. 

12. Name the parts which would be exposed if the front wall of 
chest and abdomen were cut away. State their positions. 



8 VERTEBRATE ANIMALS. 

z z. Above the diaphragm, in the thorax, are the lungs^ 
lu, lu. Between the lungs is the hearty h^ partly covered 
by fat and other things. Below the diaphragm is the 
liver^ le^ /^', the stomachy ina^ and the spiee?t, mi. Hanging 
down from the stomach is a sort of apron, 7ie^ ne; if it 
were lifted up we should find behind it the intestines and 
the kidneys. 

13. The Dorsal Cavity (a, a', Fig. i) is found in the head 
and neck as well as in the trunk of the body. If the back 
or top of a man's head were cut away the upper end of 
the dorsal cavity would be opened and we should find it 
to be a large chamber having the brain^ N\ in it. In the 
neck and trunk the dorsal cavity is a narrow tube con- 
taining in its upper two-thirds the spinal cord, JV, 

14. Man is a Vertebrate Animal. — The presence of the 
ventral and dorsal cavities with a hard partition between 
them is a chief fact in the anatomy of the human body : 
it shows that man is a vertebrate animal^ that is to say, is 
a back-boned animal., and belongs to the same great group 
as fishes, reptiles, birds, and beasts. Worms, clams, and 
insects are invertebrate a^timals, that is, have no back-bone. 

15. Man's Place among Vertebrates. — We have seen 
that man is a vertebrate, or back-boned animal. Though 
all vertebrates are alike in the general plan of their 
structure, there are such differences that zoologists di- 
vide them into classes. The most important of these 



13. Where does the dorsal cavity lie ? Name its contents and give 
their position. 

14. Why is man a vertebrate animal ? Name some other verte- 
brates. How are vertebrates distinguished from invertebrates ? Give 
examples of invertebrate animals. 

15. Why are vertebrates divided into classes? To which class 
does man belong? Name some other mammalia. How do mamma- 
lia differ from other vertebrates ? 



CHEMISTRY OF HUMAN BODY, 9 

classes is the mammalia, to which man belongs. Ordinary 
four-footed beasts, and monkeys, are also mammalia. 
The mammalia differ from all fishes, reptiles, and birds, 
first, in the possession of organs, the mainmary glands, 
which provide milk for the young; sec9nd, in possessing 
hair; third, in having the chest separated from the ab- 
domen by a diaphragm. 

16. The Intellect of Man makes him superior to any 
other animal and supreme in the world. 

His power to form conceptioiis of right and wrong and his 
knowledge of moral responsibility give him yet greater supe- 
riority. But as a material object only, do anatomists study 
man's body, and they therefore classify it among the 
bodies of other animals according as it differs from or 
resembles them in the arrangement of its parts. 

17. Chemistry of the Body. — Suppose you put a green 
stick into the fire: what happens? At first it hisses and 
gives off steam; then it begins to burn; if you draw it 
out when half burned you find it a black mass of charcoal ; 
if you put it back you find most of the charcoal will burn 
away, but some ashes will be left which you cannot 
make burn. If, instead of a green piece of wood, a man's 
body be burned, we find the same results. From this 
we learn (i) that the body contains water; (2) that it 
contains solid things which will burn; (3) that it con- 
tains solid matters, the ash, which will not burn. 

16, What makes man superior to all other animals? What gives 
him yet greater superiority? From what standpoint is n^an studied 
by anatomists? How classified ? 

17. What would be the action of fire on green wood? On man's 
body? Hence what do we learn? What name is given the materials 
which burn up ? What those which will not burn ? Of what is 
every tissue composed? In which do we find most water? Mineral 
matter? Animal matter? 



10 SUMMARY, 

The things going to make up the body and capable o 
being burned are known as animal matters; the ashes are 
mineral matters. In every tissue of the body there are 
water, animal matter and mineral matter. In some a 
great deal of wate^, as in the blood; in others a great 
deal of mineral matter, as in the bones and teeth, which 
owe their hardness to lime; in still others a great deal of 
animal matter, as in fat and muscle: but everywhere 
some of all three. 

18. Summary. — Anatomy is concerned with the form 
and structure of the parts of the body. 

Physiology with the uses of the parts and the ways in 
which they work. 

Hygiene with the conditions of life which promote the 
health of the body. 

The materials of the body are hard or soft, solid or 
liquid, and are fitted for different purposes. 

Tissue is the name given to each of the materials, 
whether blood, bone, muscle, fat, or any other. 

The organs are formed of tissues combined in various 
ways. Each organ has its own particular duty, or func- 
tion^ which in health it performs in harmony with all the 
others. 

Vertebrates are animals having back- bones — such as 
man, beasts, birds, reptiles, and fishes. Their bodies 
contain two main cavities, dorsal and ventral. In the 
dorsal cavity are the brain and spinal cord. The ventral 
cavity contains lungs, heart, stomach, liver, intestines, 
and kidneys. 

i8. What does anatomy deal with ? Physiology ? Hygiene ? 
What have we learned of the materials of the body ? Of tissue ? Of 
the organs ? Of vertebrates ? Of invertebrates ? Of mammalia ? Of 
the chemical constituents of the bodv? 



SUMMARY. II 

Invertebrates are animals having no back-bones — such as 
worms, clams, and insects. 

Alammalia is the highest of the several classos of verte- 
brates and includes man, monkeys, and four-footed 
beasts. It is characterized by the presence of mam?nary 
glands; by the fact that the ventral cavity is separated 
into chest and abdo?nen by the diaphragmj and by having 
more or less of the surface covered with hair. 

Water ^ animal matters and mineral matters compose the 
body. If it be burned the animal matters are consumed; 
the mineral matters remain in the form of ashes. 



CHAPTER II. 
THE SKELETON. 

1. The Skeleton.— By the skeleton of any animal we 
usually mean those hard parts which remain behind 
when the softer parts have decayed; as the shell of a 
clam or crab, or the bones of a bird or beast. In our own 
bodies, bones form the chief part of the skeleton; but other 
things help. A very young infant has a skeleton, but this 
skeleton is made for the most part of cartilage^ ox gristle^ 
and not of bone. As the child grows, more and more 
bone takes the place of the cartilage; but even in old age 
some cartilage remains. Moreover, a skeleton consists 
not merely of all the bones of a body, but of all the 
bones united together in their proper places. In our 
bodies they are bound together by tough stringy connec- 
tive tissue. The skeleton of the living body, as distin- 
guished from a dead skeleton made of dry bones joined 
together by wires, is therefore made up of three different 
things; namely, bones, cartilages, and connective tissue. 

2. The Bones, two hundred and six in number (see 
table, p. 22), form the hardest, and stiffest, and heaviest 



1. What is a skeleton? What change takes place in the skeleton 
of a child as it grows ? How are the bones of a skeleton put together ? 
What are the materials of the living human skeleton ? 

2. Number of bones in the skeleton ? What part of it do they 
make? How do they provide support? Protection? How con- 
cerned in movement ? 




PLATE I.-THE BOXES, JOINTS, AIS^D LIGAMENTS. 



EXPLANATION OF PLATE I. 

A front view of a human skeleton with the ligaments and some of 
the cartilages in place. 
For the names of the bones see the description of figure 3. 

a Ligaments of the Elbow-Joint. 

b The Ligament which is connected to the ventral surfaces of the bodies of 

the Vertebrae. 
€ Ligament connecting the Innominate Bone to the Spine. 
/ Ligament connecting the Innominate Bone to the Sacrum. 
g The Ligaments of the Wrist-Joint. 
h The connective-tissue Membrane which fills up the interval between the two 

bones of the Forearm. 
I A similar Membrane between the two bones of the Leg, and, lower down, 

I, ligaments of the Ankle -Joint. 
k A connective-tissue Membrane which fills up a hole in the Innominate Bone. 
n Ligaments of the Knee-Joint. 
o o Ligaments of the Toes and Fingers. 
p Capsular (bag -like) Ligament of the Hip Joint. 
q Capsular Ligament of the Shoulder-Joint. 



CARTILAGE.— CONNECTIVE, TISSUE. 13 

part of the skeleton. United in various ways, they pro- 
vide a strong framework which supports the softer 
organs, and in some places, as the skull (Fig. 6) and 
thorax (Fig. 5), make strong boxes or cages in which 
delicate organs, such as the brain or lungs, lie safe. The 
bones are also concerned in the movements of the body; 
nearly all muscles pull first on some bone or other, and 
when the bone is made to move, it of course carries with 
it the surrounding soft parts. 

3. Cartilage is what we know in meat as gristle : it is 
stiff enough to keep its shape, but can be bent with tol- 
erable ease; it is also elastic, so that it springs back to 
its proper shape, like a piece of whalebone, as soon as 
the force which has bent it ceases to act. You can easily 
feel on your nose the difference between bone and car- 
tilage. The skeleton of that part of it near the forehead 
is made of bone, and that of the lower part of cartilage. 
We can push the tip of the nose to either side, or up and 
down, but when we stop pressing, it returns to its place. 
The skeleton of that part of the ear which projects from 
the side of the head is also made of cartilage. 

Cartilage is used in parts of the skeleton which have 
to be moderately stiff, but at the same time pliable and 
elastic. 

4. Connective Tissue is used for several different pur- 
poses in the body. To understand this, let us imagine 
a quantity of very fine strands of silk, some twisted into 

3. What is cartilage ? Its properties? How used in the nose ? In 
the ear ? Throughout the skeleton ? 

4. To what may connective tissue be compared ? Name and char- 
acter of its threads ? How are the cords made? The membranes? 
The loose portion ? Where do we find networks of connective tis- 
sue ? Give an example. 



14 A CTION OF ALCOHOL OM CONNECTIVE TISSUE. 

strong cord or rope, some woven into firm bands, some 
left in loose masses, and some made up into fine net- 
work. Connective tissue consists of threads, called 
fibres^ which are much tougher and finer than any strand 
of silk. In some parts of the body these threads are 
united to form cords named ligame7its^ which bind bones 
together. Elsewhere the fibres are woven into bands or 
meinbranes which surround and support various parts. 
Lying in the crevices between different organs, forming 
a soft packing for them, we find loose fluflfy bundles of 
connective tissue. Finally, very fine networks of this 
tissue run all through most of the organs, like the veins 
or ribs through the leaf of a plant, and support and 
unite their parts. If you watch the cook cut up a piece 
of suet, you will see the stringy connective tissue which 
penetrates it in all directions, and which must be re- 
moved from the fat because it will not melt in cook- 
ing. 

5, Action of Alcohol upon Connective Tissue. — All intoxi- 
cating liquors, such as wine, brandy, whiskey, beer, etc., 
contain alcohol and are known as alcoholic drinks. One 
very serious change in the body frequently produced by 
drinking such, is an excessive growth of the connective- 
tissue networks, especially in the liver and the kidneys. 
The tissue becoming too abundant crushes and slowly 
destroys the chief liver and kidney substance which it 
was meant to protect and support. The results are in- 
curable diseases. (See pp. 132, 189.) 

6. The Bony Skeleton (Fig. 3), like the body itself, may 
be described as consisting of head, neck, trunk, and 

5. What are alcoholic drinks ? How do they affect connective tissue? 

6. Of what parts does the bony skeleton consist ? 



THE SKELETON-. 



15 




Fig. 3. — The bony skeleton. <z, h^ the skull; r, ^, the back-bone; d, the breast- 
bone; «, the collar-bone; /", the humerus; y, the ulna; g^ the radius; h^ the carpal 
bones; z, the metacarpal bones; k^ the phalanges of the fingers; j, the hip-bone; 
r, the thigh-bone; g, the knee-pan; /. the shin-bone or tibia; m, the fibula; «, the 
tarsal bones; o^ the metatarsal bones; /, the phalanges of the toes. 



i6 



THE BACK-BONE, 



limbs. Its central part, which bears 
all the rest, is a stout, bony pillar, the 
back-bone^ c, e, on the top of which is the 
skull. 

7. The Back-Bone, Vertebral Column, 
or Spine, is represented in side view in 
Fig. 4. Its upper part is made of 
twenty-four short thick bones piled 
one upon another, and each called a 
vertebra. Between each pair of verte- 
brae there is placed during life an elas- 
tic cartilaginous cushion. The lower 
part of the spine consists of two 
bones; a large one, the sacrum^ extend- 
ing from S\ to Co\\ and a much small- 
er, the coccyx^ reaching from Coi to the 
end. 

Projecting from the back of each 
vertebra (to the right in the figure) 
is a bony bar, called its spinous process. 
Through the skin .along the middle of 
the back we can feel the tips of these 
processes, and it is their presence which 
has given the name spinal column to 
the whole. 

A canal runs through the whole back- 
FiG. 4. — The spinal bouc cxccpt the coccyx_, and opens into 

column viewed from the , 1 ^ 1 1 1 1 t • 1 

leftside. C1-7, the ver- the skull-chambcr above. It IS the 

tebraeof the neck; Z>i-i2, . . 

the vertebrae behind the loWCr part of the dorsal CavitV (a, FiOf. I ), 

thorax. Z1-5, the verte- ^ ^ \ > t> /' 

brae of the loins; ^^i to and, as wc havc already learned, con- 

O71, the sacrum; Cox-^^ "^ 

the coccyx. tains the spinal cord. 

7. What other names has the back-bone? Divisions of its upper 
part ? Lower pari ? What is the spinous process ? The dorsal cavity ? 



USES OF BACK-BONE. 



i; 



8. Uses of the Mode of Structure of the Spinal Column. — 

The elastic cushions between the vertebrae make the 
whole column springy and prevent the transmission of 
sudden jars along it. By this means the soft brain, car- 
ried in the skull on its top, and the spinal cord lying in 




Fig. s. — The skeleton of the thorax, with some of the vertebrae of the neck and 
loins. ^, lower neck vertebrae; b^ the first rib; c, the collar-bone; d^ third rib; e, 
seventh rib; ^, last loin-vertebra; h^ the breast-bone; /, the shoulder-blade. 

it, are protected from injury in running and jumping. 
These cushions also allow of a little bending between 
each pair of vertebrae, so that the spine as a whole may 
be bent a good deal. But no sharp bend, such as would 
nip the spinal cord, which lies inside it, can take place 

at any one point. 

» 

8. Of what use is the cartilage between the vertebrae in running or 
jumping? In bending? 



1 8 RIBS AND STERNUM.— SKULL.— SUTURES, 

9, The Ribs and Breast-Bone (Fig. 5). — The ribs are 
twenty-four slender curved bones, twelve on each side 
of the chest. Every rib is attached behind to a vertebra, 
the top one to the first vertebra below the neck. In 
front, each rib ends in two or three inches of cartilage. 
The breast-bone or sternwn^ h, lies in front of the chest. 
Attached to its sides are the cartilages of most of the 
ribs. The two lowest ribs are not joined to the breast- 
bone and are sometimes called the free or floating ribs. 

10, The Skull (Fig. 6) is made up of twenty-nine bones 
(see table, p. 22)] those behind and above arranged to 
form the brain-box; and those in front, to support the 
face. 

The organs of four of our senses, viz., those of hear- 
ing, sight, smell, and taste, are also protected by the 
skull-bones. 

11, The Sutures, — Except the lower jaw-bone, which is 
attached to the rest of the skull by a joint, to let us open 
and close our mouths, nearly all the skull-bones are very 
firmly united. In most cases the union is by a dovetail- 
ing, like that used by cabinet-makers. Each bone has 
its edge notched and fits accurately to the edge of the 
next. This sort of junction between bones is called a 
suture. It is well seen in Fig. 6 between the bone Fr 
and those in front of, behind, and below it. 

12, How the Brain is Protected. — The dome-like form 

9. What is the number and form of the ribs? How attached 
behind ? How do they end in front ? How attached to the breast-, 
bone ? Floating ribs ? 

10. How many bones in the skull ? Use of those behind and above ? 
Those in front ? What other organs do they protect ? 

IT. How is the lower jaw-bone attached? Union of other skull- 
bones? What is a suture? 

12. What is the advantage of the dome-like form of the skull? II- 



T^HE SKULL, 



19 



of the crown of the head gives it great strength. This 
you will realize if you take an ^^^ by its ends between 
finger and thumb, and try to crush it: you will find that 
Tsp 




Fig. 6. — Side view of the skull. /*r, parietal bone; 6>, occipital bone; T. tem- 
poral bone; 6", sphenoid bone; F^ frontal bone; Z, malar, or cheek-bone; iV, nasal 
bone; Ey ethmoid bone; Z, lachrymal bone; Mx^ upper jaw-bone; Md^ lower jaw- 
bone. 



lustrate. Describe the outer layer of the bones on the sides and top 
of the brain. The next. The innermost. To what may this ar- 
rangement of the skull-bones be compared ? 



20 SKELETON OF UPPER LIMBS, 

you cannot, although egg-shell is thin and brittle. The 
bones on the sides and top of the brain-case are made 
up of three layers: an outer, tough and fitted to bear 
without breaking, blows from a heavy blunt object. Then 
comes a much softer layer which deadens any jar that 
might result from a blow on the head, and hinders its 
transmission to the brain. Inside is a layer of very hard 
bony matter, almost like glass, and admirably fitted to 
stop or turn aside any pointed instrument which might 
have penetrated the outer layers. If you turned upside- 
down a thin china teacup, wrapped around it a covering of 
raw cotton, and over this put a thin casing of tough wood, 
anything placed under the cup would be protected from 
blow^s, jars, and- piercing, much as your brain is protect- 
ed inside the skull. 

13. The Skeleton of each Upper Limb contains thirty 
bones and is attached to the trunk by the shoulder-girdle, 

14. The Shoulder- Girdle presents on each side a collar- 
hone or clavicle^ in front (//, Fig. 3, and ^, Fig. 5), and a 
shoulder-blade or scapula (/, Fig. 5), behind. The collar- 
bone and shoulder-blade unite near the shoulder-joint. 

15. The Bones of the Arm and Hand (Fig. 3) are: 
(i) the arm-bo7ie, or humerus^ /, which reaches from the 
shoulder to the elbow; (2) two forearm-bones lying side 
by side between the elbow and the wrist; the one on 
the thumb-side is the radius^ g^ and that on the little- 
finger side the ulna^ fj (3) twenty-seven hand-bones. 



13. How many bones in the forelimb? How is it attached to the 
trunk? 

14. What bone forms the front part of the shoulder-girdle ? Be- 
hind ? Where do these bones unite ? 

15. Name the bones of the arm. Give position of humerus. 
Radius. Ulna. Carpal bones. Metacarpal. Phalanges. 



BONES OF THE LEG AND FOOT. 21 

Eight of the hand-bones are small and lie close to the 
wrist-joint: they are the carpal bones^ h. Five, the meta- 
carpal bones, /, lie in the palm of the hand; fourteen, the 
phalanges, k, are placed, three in each finger and two in 
the thumb. 

16. The Skeleton of the Leg and Foot contains, like that 
of the arm and hand, thirty bones, and is attached to the 
side of the sacrum by the hip-bone. 

17. The Hip-Bones {s, Fig. 3), one on each side, meet in 
front and form, with the sacrum, a bony ring enclosing 
the lower part of the cavity of the abdomen or belly. 
This ring is named Xh^ pelvis. 

18. The Bones of the Leg and Foot are: (i) the thigh- 
bone, or femur, r, reaching from the hip-joint to the knee: 
it is the longest bone in the body; (2) the tibia or shin- 
bone, I, and fibula, m, running side by side from knee to 
ankle-joint; (3) the knee-pan or patella, q, in front of the 
knee-joint; (4) twenty-seven foot-bones. 

Seven of the foot-bones, named tarsal bones, n, lie below 
the ankle-joint and support the heel; five metatarsal bones, 
0, follow these; and fourteen phalanges, p, are found in 
the toes, two in the great toe and three in each of the 
others. 



16. How many bones in the leg? How attached to the sacrum? 

17. Describe the hip-bones. 

18. Name the leg-bones. State position of femur. Tibia. Fibula. 
Patella. Tarsal bones. Metatarsal bones. Phalanges. 



22 THE BONY SKELETON. 

TABLE OF THE SKELETON. 

The Bony Skeleton: 206 bones. 

Head, Nfxk, and Trunk: 80 bones. 
Skull : 29 bones. 

Brain-case, 8 bones, namely : 

Occipital bone, at back of head 

Frontal bone, in forehead 

Parietal bones, on top and sides of head 

Temporal bones, in the temples 

Sphenoid bone, on floor and sides of brain-box 

Ethmoid bone, between top of nose and brain case. 



Face-bones, 14, namely: 

Lower jaw-bone 

Vomer, between the nostrils 

Upper jaw-bones 2 

Palate-bones, supporting part of the roof of the mouth. ... 2 
Malar bones, supporting the cheek below and outside 

the eye 2 

Lachrymal bones, between nose and eye-socket 2 

Nasal bones, on roof and sides of nose 2 

Turbinate bones, inside the nose 2 

— 14 

Ear-bones, 6, three on each side, namely: 

Malleus, or hammer-bone I 

Incus, or anvil-bone i 

Stapes, or stirrup-bone i 

3X2= 6 
Hyoid bone, to which the root of the tongue is attached i 

29 
Vertebral Column: 26 bones, namely: 

Cervical (neck) vertebrae 7 

Dorsal vertebrae, at back of thorax 12 

Lumbar (loin) vertebrae 5 

Sacrum i 

Coccyx I 

~ 26 

Ribs : 24 bones, on each side twelve 24 

Sternum (breast-bone) i 

80 



THE BONY SKELETON. 23 

Limbs and the Bones uniting them to the Trunk: 126 bones. 
Shoulder-girdle: 4 bones, on each side two, namely: 

Clavicle, or collar-bone I 

Scapula, or shoulder-blade I 

2X2 = 4 
Arms: 60 bones, on each side thirty, namely: 

Humerus i 

Ulna I 

Radius i 

Carpal or wrist bones 8 

Metacarpal bones 5 

Phalanges 14 

30 X 2 = 60 

Hip-bones : on each side one 2 

Legs: 60 bones, on each side thirty, namely: 

Femur, or thigh-bone i 

Patella, or knee-pan i 

Tibia, or shin-bone i 

Fibula, or ** small bone of the leg" i 

Tarsal (ankle and heel) bones 7 

Metatarsal bones 5 

Phalanges 14 

30 X 2 r= 60 

126 



CHAPTER III. 

THE STRUCTURE, COMPOSITION, AND HYGIENE OF THE 
BONY SKELETON. 

1. The Parts of the Humerus.— Though bones differ in 
shape and size, we may get a pretty good idea of the way 
they are all built by studying the humerus, Fig. 7. This 
presents a central rounded portion, or shafts bearing at 
each end an enlargement, the articular extremity. The 
shaft lies between the dotted lines x and z. One use of 
these large ends is to give more room for the fastening 
on of muscles. 

2. Internal Structure. — If the humerus be sawed in two 
lengthwise (Fig. 8) we find that its shaft is hollow; the 
space is the marrow cavity^ a^ and during life is filled 
with a kind of fat. We also see that there are two kinds 
of bony substance; one is hard and close, the other loose 
and spongy. The hard bone, ^, lies on the outside, and 
is thick in the shaft; it forms only a thin layer in the 
extremities, which are filled with spongy bone, c. The 
large marrow-cavity does not extend into the extremi- 
ties. 

3. Why Bones are Hollow. — All bones either contain a 
marrow-cavity or are filled up with loose spongy tissue. 

1. Describe the humerus as viewed on its outside. For what are 
its large ends useful ? 

2. What would we find inside the shaft ? The extremities ? 

3. What do all bones contain ? Wh}'^ are they not filled with hard 
bone? Why are the iron pillars used in building made hollow ? 



THE HUMERUS. 



25 



X 




Fig. 7. 



m 



mt 






wm 



M^im^t 



^^^. 



Fig. 



Fig. 7. — The right humerus, seen from the front. 

Fig. 8.— The humerus cut open, a, marrow-cavity ; b^ hard bone; c:, spongy 
bone ; d^ cartilage. 



26 NOURISHMENT OF BONE. 

If they were of hard bony substance throughout, they 
would be either very heavy and unnecessarily strong, or 
else too slender to give surface enough for the attach- 
ment of muscles and other organs. A given quantity 
of material if arranged in the form of a tube will bear a 
much greater weight than if it were made into a solid 
rod of the same length as the tube. For this reason, 
iron pillars used in buildings to support ceilings and 
floors, are hollow. To cast them solid would make them 
much heavier without great increase of strength. 

4. How Bones are Nourished. — When the humerus is in 
the body, it is closely surrounded by a connective-tissue 
membrane, the periosteum. This membrane is full of 
blood which nourishes the bone by means of innumer- 
able little channels passing into and branching all 
through it. These channels are too small to be seen 
without a microscope, but even the most close-grained 
part of every bone is full of them. As long as the hume- 
rus is growing thicker, the periosteum is making new 
bone on its inner side. If this membrane is peeled off, 
the bone dies. The parts of the articular extremities 
(Q), TV, Cpl^ Fig. 7) which meet other bones at the 
shoulder and elbow-joints are covered by cartilage instead 
of periosteum. 

5. The Chemical Composition of Bone. — The dried bone 
of a man in middle life, consists of two parts of mineral to 
one part of animal matter. The minerals give the bone its 
hardness and stiffness; they may be obtained separate 

4. With what is the humerus surrounded ? How does the perios- 
teum nourish the bone ? What happens if it be peeled off? Where 
is cartilage found instead of periosteum ? 

5. Of what does the dried bone of a mtddle-aged maa consist? 



COMPOSITION OF BONE. 2J 

by thoroughly burning a bone. The animal matter may 
be obtained by soaking a bone for a few days in an acid 
which dissolves away the minerals. 

The mineral matter by itself has still the form of the 
bone, but is very brittle. The animal matter by itself 
also has the form of the bone, but is soft and easily bent. 
The two mixed together, as they are in the skeleton, 
make our bones hard enough to support the rest of the 
body, and tough enough not to be easily broken. The 
animal matter also makes the bones tolerably flexible 
and elastic: some savages make their bows from the ribs 
of large animals. 

In childhood the animal matter, and in old age the 
mineral matter, of bone is more abundant than in middle 
life. Therefore the bones of an old person are brittle 
and easily broken, while those of a child often bend 
when the bones of an adult would break. 

6. Gelatin. — When a bone is boiled in water for several 
hours, most of its animal matter is turned into gelatin^ 
and dissolved in the water. Gelatin is a useful food; 
most of that which we buy for making jelly is made from 
bones. For soup we use bones as well as meat, and by. 
long boiling extract the gelatin from them. In a piece 
of meat as ordinarily cooked most of the gelatin remains 
in the bones, which are therefore useful for soup and 
should not be thrown away. 



What is the use of the minerals ? How may they be obtained sepa- 
rate? How the animal matter? Characters of mineral matter ? Of 
the animal ? Use of having both in a bone ? At what time of life is 
the animal matter most abundant ? Why are an old person's bones 
easily broken ? 

6. How may we get gelatin from a bone ? Why are bones left 
from a piece of meat useful in making soup ? 



28 HYGIENE OF BONES, 

7. Hygiene of the Bony Skeleton.— Except hair and teeth, 
bones are the parts of the dead body which most resist 
decay. Nevertheless living bone is readily altered in 
shape, especially in young persons, by continued or fre- 
quently repeated pressure or strain. This is well illus- 
trated by the curious forms which sorne nations give to 
their skulls (Fig. 9) by tying boards or bandages on the 
heads of their children. 




Fig. 9.— Skull of a child of the tribe of Chinook Indians (inhabiting tne neigh- 
borhood of the Columbia River), distorted by tight bandaging so as to assume the 
shape considered elegant and fashionable by the tribe. 

8. Why Children should have their Feet Supported and 
should Sit Straight. — The bones of a child being rich in the 
softer animal matter are tolerably flexible, and may be 
readily made to grow out of shape. Therefore children 
should never be kept sitting on a bench so high that the 
feet are not supported. If this precaution be neglected 
the thigh-bones become bent over the edge of the seat 
by the weight of the rest of the limb and may be made 
crooked for life. 

7. What parts of the dead body decay most slowly ? How may 
living bone be altered in form ? Illustrate. 

8. Why should the feet of children be supported when sitting? 
Why is it important to sit straight ? Why shcruld children not be 
encouraged to walk too soon ? 



THE INSTEP. 



29 



For the same reason it is important to sit square and 
straight at the table when writing or drawing, and with 
the shoulders level: otherwise the spinal column may 
become curved to one side. 

Young children should not be encouraged to walk too 
early, lest they grow bow-legged, their leg-bones not 
being stiff enough to bear the weight of the upper part 
of the body. 

9. Usefulness of the Arch of the Instep.— The bones of the 
foot (Fig. 10) are arranged to make a springy arch which 




1 

Til CI3 """sm 3 

Fig. 10.— The skeleton of the foot. Ca, the heel-bone; C/, C//, C3, iV, some of 
the tarsal bones; Os^ the front end of the metatarsal bones; 7V», the surface which 
makes the ankle-joint with the tibia and fibula, and bears the weight of the body 
in standing and walking; M\^ metatarsal bone of the great toe. 

rests on the ground by the heel-bone, Ca^ behind, and by 
the front ends, Os^ of the metatarsal bones in front. On 
the crown of the arch is the surface, Ta^ where the foot 
joins the leg at the ankle-joint. At this joint the weight 
of the body is borne. The many small bones in the arch 
glide over one another a little when the crown of the 
arch is pressed upon; but spring back into place when 
the pressure is removed. This elastic arch of the foot 

9. Describe the construction of the instep. Why is tt arched and 
elastic? To what may it be compared? How may we learn some- 
thing of the jarring saved us by the instep ? Illustrate the usefulness 
of a well-arched instep in prolonged walking. 



30 HIGH-HEELED BOOTS, 

lessens the jarring which would be transmitted to the 
spinal column, and thence to all the rest of the body, 
were the foot flat or rigid. A well-arched instep is 
therefore rightly considered beautiful; it makes the step 
easier and more elastic. 

We may compare it to a carriage-spring, which gives 
a gentle sway to the vehicle and prevents sudden jolting. 
How much jarring the instep saves us, may be readily 
learned by walking across a room on the heels. For a 
steady, even, long-continued tramp, like that of a police- 
man, a foot well-arched under the instep is of great im- 
portance: it not only saves the upper parts of the body 
from injury, but much diminishes the fatigue of walking. 
Men who desire to join the police force but who are 
"fiat-footed," are rejected; experience having proved 
that such persons cannot walk the daily " rounds.** 

10. Why High-heeled Boots are Hurtful. — When we 
walk on the heels, we are jarred at each step because the 
arch of the instep is not used as a spring. If we walk on 
the toes, this is not the case, as the elastic front half of 
the foot is brought into action. But walking or running 
on the toes is fatiguing because it demands extra muscu- 
lar effort. Boots with high heels lead practically to walk- 
ing on the toes. The sole of the boot forms such a 
slope, high behind and low in front, that the whole foot 
slides forward on it, and the heel has no place on which 
it can bear firmly and take its share of the work. The 
arch of the instep is made useless, and the toes slip along 



lo. Why are we not as much jarred when we walk on our toes as 
if we walk on our heels? Why is walking on the toes fatiguing? 
What are the consequences of wearing high-heeled boots ? Of boots 
with pointed toes ? 



NARROW'TOED BOOTS, 



31 



until they are squeezed into the toe of the boot; and on 
them all the weight of the body is there carried. The 
so-called "French heel/' placed right under the arch of 
the instep, makes that piece of Nature's mechanism per- 
feetly useless. 

The results are an awkward, ungraceful gait; and un- 
due fatigue, leading to omission of proper healthy exer- 
cise, to the loss of many innocent pleasures, and often to 



f 




\ 




/ 


, \ 


/ 




^ / 




^ \ 




1 




•W 




^ 






Fig. II.— ^, natural form of the sole of the foot; B, the same with the outline of 
an ordinary fashionable boot; C, Z>, feet which have been made to grow out of form 
by wearing such a boot. 

neglect of duties whose performance necessitates walk- 
ing. 

Continued wearing of narrow-toed boots, especially if 
they have also high heels, leads to permanent distortion 
of the foot. Its front part being forced into the toe of 
the boot by the weight of the body, the toes are pushed 
out of place, frequently pressed over one another 
(Fig. 11), and made useless; while corns and bunions are 



32 



TIGHT LACING, 



developed, making the walk still more painful and less 
graceful. 

11. The Evils of Tight Lacing can only be properly un- 
derstood after we have studied the use and working of the 
heart and lungs (Chap. XV.). With our hands we can 
press in our lower ribs and narrow the chest-cavity; but 




Fig. 12. — Skeleton of the chest of a woman, twenty-three years of age, deformed 
by tight lacing. Compare with the natural skeleton, Fig. 5. 

as soon as we cease the pressure, the ribs spring back 
to their place. If, however, a tight corset be worn for 
weeks or months, the ribs gradually yield to it and 
change their shape. The result is a deformed chest- 
skeleton (Fig. 12). The lower ribs press on the liver, 



II. How does tight lacing alter the ribs ? What organs are injured 
in consequence ? 



BROKEN BONES 33 

injuring it; and the bottom of the chest-cavity is so nar- 
rowed that the heart and lungs are cramped for room. 

12. What should be Done when a Bone is Broken. — When 
a bone is broken, it is said to h^ fractured. The muscles 
on each side of the break are very apt to pull the pieces 
of the bone out of place. Therefore the broken bone 
needs to be set into place, and then held by splints and 
bandages so that the ends be kept together until they 
unite. To set a broken bone, often needs great skill and 
a thorough knowledge of anatomy. A medical man 
should be summoned without delay, as the parts around 
the fracture usually swell very rapidly, making the 
exact position of the break hard to find out, and the re- 
placement of the pieces of the bone more difficult. Until 
skilled aid arrives, the sufferer should be kept as quiet 
as possible: cloths dipped in cold water and frequently 
renewed may be applied to keep down swelling and in- 
flammation. 

13. How a Broken Bone is Knit together again. — A 
watery liquid first collects between and around the 
broken ends. This gradually thickens, becoming jelly- 
like, and then of the hardness of gristle, though it does 
not become actual cartilage. It is chiefly made by 
the periosteum, which becomes very active where the 
bone is broken, and makes this uniting material in such 
abundance that it forms quite a thick ring all round 
the fracture. This ring, named the callus, is afterwards 

12. What is a fracture ? Why does a broken bone require to be 
set ? Why should a doctor be summoned at once ? What should be 
done until he arrives ? 

13. What first happens when Nature begins to repair a broken 
bone? Next? What makes this first uniting material ? What is the 
callus? Its use? What finally becomes of it? What takes place 
inside the callus ? 



34 THE CALLUS. 

hardened by lime being deposited in it. It forms a sort 
of natural splint, and strengthens the bone until the 
ends have firmly grown together. Then it is slowly 
absorbed, and after a few months hardly a trace of 
it is left. The callus may be compared to the metal 
band which is used to hold together the two parts of 
a broken umbrella-handle. Inside the callus, new bone 
slowly forms in the gristly layers between the broken 
ends, and unites them. The surgeon usually removes 
his artificial splints when the callus has become well 
developed. 



CHAPTER IV. 
THE ORGANS OF MOVEMENT • MUSCLES AND JOINTS. 

1, Articulations. — Wherever two bones meet in the body 
an articulation is formed. In some articulations the bones 
are fixed immovably together, as in the sutures of the skull, 
(p. i8); in others, to enable us to move, the ends of the 
bones are so shaped and so fastened together that one 
can slide over the other. Articulations of this kind are 
called y^//^/j-. Joints may be compared to hinges between 
bones: examples are found between the lower jaw-bone 
and the rest of the skull; at shoulder, elbow, wrist, hip, 
knee, ankle; and between the bones of the fingers and toes. 

2. The Movements of the Body are brought about by 
soft red organs named muscles. The lean of meat is mus- 
cle, so every one knows what dead muscle is like. Living 
muscle has the power of shortening, or contracting^ with 
great force. When a muscle contracts it pulls its ends 
together and swells out in the middle; in other words, 
// becomes shorter and thicker. If you watch the front of 
your forearm while you forcibly bend your wrist, you 
can observe, through the skin, the muscles becoming 
shorter and thicker. Nearly always the two ends of a 

1. What is an articulation ? Of what kind of articulation are the 
sutures of the skull examples ? What is a joint? Name some joints. 

2. What is the use of muscles ? What is dead muscle like ? What 
power has living muscle ? How does it change its shape in contract- 
mg? Illustrate. To what are the ends of a muscle usually fixed ^ 
What results when a muscle contracts ? 



36 HIP-JOINT, 

muscle are attached to separate bones, between which 
a joint is placed; and when the muscle contracts it pro- 
duces movement at the joint. The joints and muscles 
are the chief organs of movement. 

3. Joints. — As an example of a joint we may take 
that at the hip (Fig. 13). 




Fig. 13.— The hip-joint, sawed through its middle. The rounded head of the 
thigh-bone is seen to fit into the cup or socket of the hip-bone, a, cartilage hn- 
ing socket; ^, cartilage covering end of femur; c, ^, capsular ligament; LT^ round 
ligament. 

On the outer side of the hip-bone {s^ Fig. 3) is a cup- 
like hollow which receives the round upper end of the 
thigh-bone. Lining the cup is a thin layer of cartilage, 
and covering the end of the thigh-bone is another. The 
cartilage is extremely smooth and is kept moist by a few 
drops oi joint'Oil^ or syjiovial liquid^ so that the end of the 

3. Describe the hip-joint. What use is the cartilage ? The syno- 
vial fluid? The ligaments ? 



BALL-AND'SOCKE T JOIN TS.— HINGE-JOINTS. 37 

femur rolls very easily in the hollow, or socket. The carti- 
lage forms a yielding cushion which hinders the bones 
from scratching or chipping one another. 

To keep the bones in place and prevent too free move- 
ment, strong bands of connective tissue, called ligaments^ 
unite them, being fixed above to the hip-bone and below 
to the femur. Many powerful muscles also pass from one 
bone to the other, and keep them pressed close together. 

4. Ball-and-Socket Joints. — A joint like that at the 
hip, where the round end of one bone fits into a cavity 
in which it can roll in any direction, is called a ball-and- 
socket joint. It allows more free movement than any 
other kind. At the shoulder there is another ball-and- 
socket joint. 

5. Hinge-Joints. — In hinge-joints the ends of the bones 
are not evenly rounded on all sides, but one bone has 
projecting ridges which slide in grooves on the other. 
The result is that the only movements possible are to and 
fro, or in one direction and back again, like a door on its 
hinges. 

The knee is a hinge-joint: it can only be bent and 
straightened; or, as physiologists say, flexed d^nd, extended. 
Between the phalanges of the fingers there are other 
hinge-joints. 

6. Pivot-Joints. — In pivot-joints one bone rolls round 
another. 

A good example is the joint which permits us to turn 
the head from side to side. 

The uppermost vertebra (Fig. 14), which carries the 

4. What is a ball-and-socket joint ? 

5. Describe a hinge-joint. Examples. 

6. What are pivot-joints ? Describe the atlas. What is the odon- 



38 



PIVOT-JOINTS. 



skull, has been fancifully named the atlas vertebra^ after 
the fabled giant of antiquity who was believed to bear 
the heavens on his shoulders. It is ringlike in form and 
the space which it surrounds is separated by a ligament, 
Z, into a smaller front and larger back division. In the 
larger division the spinal cord lies. Into the smaller pro- 
jects a bony peg (Z>, Figs. 14 and 15), called from its 
shape the toothlike or odontoid process^ which springs from 



.Aa Fas 




Fig. 14. 



Fig. 



Fig. 14.— The atlas vertebra sf ei from above. Fig. 15.— The axis vertebra, 
L^ the ligament which divides the space surrounded by the atlas into a 'back 
portion, containing the spinal cord; and a front portion, containing the odontoid 
process, Z>, of the axis, round which the atlas rolls when we turn the head to either 
side. 

the second or axis vertebra. Knobs on the under side of 
the skull fit into the hollows {^Fas^ Fig. 14) on the atlas: 
when we turn the face to right or left the atlas, carrying 
the skull with it, rolls around the odontoid process. 

Another kind of pivot-joint is found in the forearm. 
Lay the hand and forearm flat on a table, palm upwards. 
Without moving the shoulder-joint at all, it will be easy 



told process ? What happens at the joint between atlas and axis 
v^hen we turn the face to one side ? Where is there another kind of 
pivot joint ? What is the position of radius and ulna v^rhen the palm 
of the hand is turned up ? When turned down ? 



EXPLANATION OF PLATE IL 

A view of the muscles situated on the front surface of the body, 
seen in their natural position. It must be understood that beneath 
these muscles many others are situated, which cannot be represented 
in the figure. 

Muscles of the Face, H^ad, and Neck: 

1. Muscle of the Forehead. This, together with a muscle at the back of the 

head, has the power of moving the scalp. 

2. Muscle that closes the Eyelids. The muscle that raises the upper eyelid 

so as to open the eye, is situated within the orbit, and consequently 
cannot be seen in this figure. 

3. 4, 5. Muscles that raise the Upper Lip and angle of the Mouth. 

6, 7. Muscles that depress the Lower Lip and angle of the Mouth. By the 
action of the muscles which raise the upper lip, and those that depress 
the lower lip, the lips are separated. 

8. Muscle that draws the Lips together, so as to close the IMouth. 

9. Muscle of the Temple (Temporal Muscle). 

10. Masseter Muscle. 9 and 10 are the two chief muscles of mastication, for 

when they contract, the movable lower jaw is elevated, so as to crush 
the food between the teeth in the upper and lower jaws. 

11. Muscle that compresses the Nostril. Close to its outer side is a small 

muscle that dilates the nostril. 

12. Muscle that wrinkles the Skin of the Neck, and assists in depressing the 

lower jaw. 

13. Muscle that assists in steadying the Head, and also in moving it from side 

to side. 

14. Muscles that depress the Windpipe and Organ of Voice. The muscles 

that elevate the same parts are placed beneath the lower jaw, and can- 
not be seen in the figure. 

Muscles that connect the upper extremity to the trunk. Portions 
of four of these muscles are represented in the figure, viz. : 

15. Muscle that elevates the Shoulder. Trapezius Muscle. 

17. Great Muscle of the Chest, which draws the Arm in front of the Chest 

(Great Pectoral Muscle). 

18. Broad Muscle of the Back, which draws the Arm downwards across the 

back of the Body (Latissimus Dorsi). 

19. Serrated Muscle extends between the Ribs and Shoulder-blade, and draws 

the shoulder forwards and rotates it, a movement which takes place in 
the elevation of the arm above the head (Serratus magnus). 



At the lower part of the truuk, on each side, may be seen the large 
muscle which, from the oblique direction of its fibres, is called, 

20. Outer Oblique Muscle of the Abdomen. 

Several muscles lie beneath it. The outline of one of these, 

21. Straight Muscle of the Abdomen, may be seen beneath the expanded 

tendon of insertion of the oblique muscle. These abdominal muscles, 
by their contraction, possess the power of compressing the contents of 
the abdomen. 

Muscles of the upper extremity. 
16. Muscle that elevates the Arm (Deltoid Muscle). 

22. Biceps or Two-headed Muscle (see also page 41). 

23. Anterior Muscle of the Arm. This and the Biceps are for the purpose of 

bending the Fore Arm. 

24. Triceps, or Three-headed Muscle. This counteracts the last two muscles, 

for it extends the Fore-arm. 

25. Muscles that bend the Wrist and Fingers, and pronate the Fore-arm and 

Hand— that is, turn the Hand with the palm downwards. They are 
called the Flexor and Fi'onator Muscles. 

26. Muscles that extend the Wrist and Fingers, and supinate the Fore-arm 

and Hand— that is, turn the Hand with its palm upwards. They are 
called the Extensor and Supinator Muscles. 

27. Muscles that constitute the ball of the Thumb. They move it in different 

directions. 

28. Muscles that move the Little Finger. 

Muscles which connect the lower extremity to the pelvic bone. 
Several are represented in the figure. 

29. Muscle usually stated to have the power of crossing one Leg over the 

other, hence called the Tailor's Muscle, or Sartorius; its real action is 
to assist in bending the knee. 

30. Muscles that draw the Thighs together (Adductor Muscles). 

31. Muscles that extend or straighten the Leg (Extensor Muscles). The 

muscles that bend the leg are placed on the back of the thigh, so that 
they cannot be seen in the figure. 

Muscles of the leg and foot : 

32. Muscles that bend the Foot upon the Leg, and extend the Toes. 

33. Muscles that raise the Heel— these form the prominence of the calf of the 

Leg. 

34. Muscles that turn the Foot outwards. 

35. A band of membrane which retains in position the tendons which pass 

from the leg to the foot. 

36. A short muscle which extends the Toes. 

The muscles which turn the foot inwards, so as to counteract the 
last named muscles, lie beneath the great muscles of the calf, which 
consequently conceal' them. The foot possesses numerous muscles, 
which act upon the toes, so as to move them about in various direc- 
tions. These are principally placed on the sole of the foot, so that 
they cannot be seen in the figure. Only one muscle, 36, which assists 
in extending the toes, is placed on the back of the foot. 




PLATE II -THE SUPERFICIAL MUSCLES OP THE FEOXT OP THE BOLT. 



MUSCLES. 



39 



to turn the hand, palm downwards. This is done (Fig. i6) 
by rolling the lower end of the radius, which carries the 
hand, around the ulna. When the palm is upward the 
radius and ulna lie side by side as shown at A\ while it 
is being turned downward, the lower end of the radius 
rolls around the ulna and at 
last crosses it to get on its ^*^' 
inner side, as shown at B. 



..-cf 



u 



7. ,The Muscles of the human 
body are more than five hun- 
dred in number.^ T^^^Y vary in 
size from tiny ones^ inside the 
ear,^not half an inch long, ta 
ithat (29,Plate II.) which passes 
from the pelvis to the tibia and 
i^ighteen inches or more in 
length. All muscles have the 
powder of shortening and thus 
of pulling other parts (usu- 
ally bones) to which their 
ends may be attached. After 
a muscle has shortened and 
done its work, it lengthens 
again, or relaxes. In addition 
to their chief function of moving the body, muscles 
clothe the skeleton and make the form round and 
shapely; they aid in enclosing cavities) as the mouth 
and abdomen;! and they help to hold bones together at 
joints. 

7. How many muscles in the body? Their size? On what do our 
movements depend ? What other functions have muscles? 



A 



FiG. 16.— Bones of the forearm 
and hand. A^ the palm turned 
forwards or upwards {supination)^ 
and the radius and ulna parallel; 
B^ the palm turned downwards or 
backwards {pronation)^ and the ra- 
dius crossing the ulna. 



40 



MUSCLES OF THE ARM, 



8. The Parts of a Muscle. -^iln 

its most common form, a muscle 
consists of a red x soft middle 
part,;called its ^<f//v,;which tapers 
towards each end and passes into 
very tough white cords named 
te7idons or sinews. [The tendons 
ma}^ be compared to ropes, tying 
the working part of the muscle, 
\namely its belly,/' to the bones 
which the muscl6 has to mov^ 
The hard cord-like tendons of 
the muscles which bend the 
fingers can easily be felt through 
the skin in front of the wrist. 

9. The Muscles of the Arm, 
some of which are shown in 
Fig. 17, may be taken to il- 
lustrate the structure and ar- 
rangement of nearly all muscles. 
We see that some (8, 11, 12) pass 
over the elbow-joint from arm to 
forearm. Others (14, 15, 16, 17, 
18) start from the ulna or radius 
and pass over the wrist-joint to 
the hand. Near the wrist most 
of them end in slender tendons, 
which are kept in place by a 

Fig. ly.-The muscles on the Strong cross-band of conuective 

back of the hand, forearm, and . /. .\ a^u i • i_ i. 

lower half of the arm, as ex- tlSSUC (+ +). 1 he Skm haS been 

posed on dissecting away the ^ . , - 111 

skin. dissected awav from the back 




8. What parts has a muscle ? Their uses ? 

9. Describe the course of some of the arm-muscles. 



THE BICEPS MUSCLE, 4 1 

of the middle finger to show the ending of tendons 
on it. 

10. How we may Recognize the Working of a Muscle. — 

The shortening of a muscle, when it is at work, is suf- 
ficiently shown by the way it pulls the bones; as when 
we bend the elbow-joint or the fingers. The thickening 
may be seen and felt on the biceps-muscle (Fig. i8), in 
front of the humerus, when the elbow is bent; or on the 
muscles of the ball of the thumb, when we move the 



Fig. i8. — The biceps-muscle and the arm-bones, to illustrate how the elbow-joint 
is bent, when the biceps-muscle contracts and becomes shorter and thicker. 

thumb so as to make it touch the little finger. When a 
muscle contracts, its belly becomes harder. The swell- 
ing and hardening of a contracted muscle are daily illus- 
trated when a school-boy bends his elbow as powerfully 
as he can and then invites another to feel his " biceps.** 

11. Muscles not directly attached to the Skeleton. — Most 
of these surround openings, which they close when they 
contract. Thus around the mouth-aperture is a ring 

10. How may we recognize the shortening of a working muscle ? 
The thickening ? The hardening ? 

11. Give examples of muscles not directly attached to bones. 



42 BOW THE MUSCLES ARE CONTROLLED. 

of muscle [orbicularis oris, 8, PI. II.) which shuts the mouth, 
or if more vigorously contracted purses out the lips, as 
when a child holds up its mouth to be kissed. A similar 
ring-like muscle [orbicularis palpebrarum, 2, PI. II.) sur- 
rounds the opening between the eyelids and closes the 
eyes. 

12. How the Muscles are Controlled. — It is very clear 
that we could not do what we wanted to do if our mus- 
cles contracted at random: they must be held in control; 
kept at rest when their action is not needed, and made to 
work when it is. If the muscles closing the mouth con- 
tracted when we tried to put food into it we should be 
in a bad plight. .AH the muscles are directed and guided 
in their work by the nervous systeny(Chap. XVII.). ^^From 
the brain and spinal cord nerves run to them, governing 
all and making them work together in harmonyy those 
which straighten the elbow-joint are not, for example, 
permitted to pull when we desire to bend it. In convul- 
sions the controlling nervous organs cease their guidance; 
the muscles contract in all sorts of irregular and useless 
ways; and, often, since those which produce exactly 
opposite movements contract at the same moment, the 
whole body is made stiff. 

13. Involuntary Muscles. — The muscles hitherto con- 
sidered are all more or less under the control of our will. 
We can make them contract or prevent their contraction as 
we choose. They are called the voluntary muscles. There 
are other muscles whose working we cannot control; 

12. What power must we have over our muscles ? What is the use 
of the nerves of the muscles ? In what organs do they commence ? 
How do the muscles behave during a fit of convulsions ? Why ? 

13. What are voluntary muscles ? Involuntary ? Where found ? 
Use ? 



INVOLUNTARY MUSCLES. 



43 



they are named involirntary muscles, 'involuntary muscles 
are not attached to the skeleton nor concerned in our 
ordinary movements,/ but lie in the walls of hollow 
organs, as the stomach and intestine (Chap. XI.). When 
they contract they push along the contents of these 
organs. 

14. As a general rule all the movements most.necessary 
for keeping the body alive, as those which cause the blood 




Fig. 19.— The muscular coat of the stomach. 

to flow to all organs or food to travel along the ali- 
mentary canal, are taken by Nature out of our control, 
and performed by involuntary muscles. It is, however, 
impossible to draw a sharp line between voluntary 
and involuntary muscles. The breathing muscles are 
partly subject to our will : any one can draw a long 
breath when he chooses. But in ordinary quiet breath- 
ing, we are quite unconscious of the working of these 

14. What class of movements is not subject to our will ? Illustrate. 
What is said concerning the breathing muscles ? Give instances in 
which other voluntary muscles contract against our will. 



44 STANDING, 

muscles; and even when we pay heed to it, our control 
is limited: no one can hold his breath long enough to 
suffocate himself. Any one of the voluntary muscles 
may be thrown into activity, independently of or even 
against the will, as we see in the "fidgets" of nervous- 
ness. When we call any muscle voluntary, we mean that 
it may be controlled by the will, but not that it neces- 
sarily always is so. 

15. Standing. — There are two reasons why a young 
infant cannot stand: the first is that its skeleton is not 
firm enough to bear its weight; the second is that it can- 
not guide and manage its muscles. After the bones are 
strong enough a child has still to learn to stand. We 
all at last become by practice able to do so without 
thinking about it; but standing always demands that a 
great many muscles shall be at work, and be guided by 
the brain. The part the brain takes, although we usu- 
ally know nothing about it, is shown by the fall which 
results from a violent knock on the head. This may 
break no bone and injure no muscle, and yet the man who 
has received it falls stunned and helpless to the ground. 
His brain has been so shaken that it ceases for a time 
to do its work, and the consequence is that the muscles, 
released from control, cease to do their work; so until 
the brain recovers, the man cannot stand. 

16. How our Brains come to Control the Muscles without 
our being Conscious of it. — A child learning to stand has 
to take a great deal of trouble; it has to think about 
what it is doing all the time. After a while, it gives less 

15. Why cannot an infant stand? How is the brain concerned in 
standing? In what way is this fact shown ? 

16, Give an example of an action once performed with trouble 



UNCONSCIOUS MUSCULAR ACTION, 4$ 

and less thought to the proper action of the muscles of 
standing; and at last its brain does the work without any 
thinking about it at all. The child then stands, as it 
breathes, almost or quite unconsciously. This is a very 
curious and a very important fact. It is but one example 
of many, showing that actions of our muscles which once 
cost thought and effort, come at last to be done with- 
out either. Practice not only ^^ makes perfect," it also 
makes easy that which before was difficult. The trouble 
with which we learn to ride or swim, or strike the proper 
keys of a piano, thinking about every necessary move- 
ment, and the ease with which we come at last to do 
these things, are other examples of the same fact. When 
any muscular action which was at first performed with 
difficulty and by *' willing" to do it, comes to be per- 
formed almost unconsciously, without our will, we say a 
habit has been formed. When the brain and muscles 
have been trained to work together in this unconscious 
way, it is as hard or harder to break the habit than it 
was to acquire it. A practised rider would have to take 
a good deal of trouble to fall off his horse under ordi- 
nary circumstances, or a good swimmer to drown himself. 
This tendency of the brain and muscles to do at last 
without the will, or against it, that which they have 
often done before in consequence of the will, is of the 
greatest importance. It is the physiological reason for 
acquiring good habits and avoiding bad. The more 
often we do anything, the easier it is to do it again, and 
the harder to avoid doing it. 

which at last comes to be done unconsciously. Other illustrations. 
What is a habit? How do habits come to control us? What is the 
physiological reason for forming good habits and avoiding bad ? 



46 



BTANLtNG. 



I 



il 



17. The Muscles concerned in Standing. — In consequence 
of the flexibility of the ankle-, knee-, and hip-joints, a 
dead body cannot be balanced on 
its feet, as a marble statue may be. 
When a man stands, the joints would 
beiid, were they not braced and held 
firm by muscles. When we stand, mus- 
cles (Fig. 20, i) in front of the ankle- 
joint, and others (/) behind it, con- 
tracting at the same time, keep that 
joint from yielding. In the same way, 
muscles (2) in front of the knee- and 
hip-joints, are opposed by others (//) 
behind them, and when we stand, both 
contract and keep those joints rigid. 
The muscles (///) which run from the 
pelvis to the back of the head, in like 
manner pull against others (3 and 4) 
which run from the pelvis to the lower 
end of the breast-bone, and from the 
upper end of the breast-bone to the 
front part of the skull; their bal- 
anced contraction keeps the head erect. 
If one falls asleep while sitting or 
standing, the chin drops, because the 
muscles holding the head upright have 
relaxed their vigilance, and its front 
part is heavier than its back. Since 
the degree to which each muscle contracts when we 



i 



\ 



I 



Fig. 20. — Diagram 
illustrating the mus- 
cles (drawn in thick 
black lines) which pass 
before and behind the 
joints, and by their 
balanced activity keep 
the joints rigid and the 
body erect. 



17. How do the muscles enable us to stand ? Why does the head 
fall forward if one goes to sleep standing ? Why does it take time to 
learn to stand ? 



A FEW HINTS FOR TEACHERS. 47 

Stand, must be exactly equal to the contraction of its 
antagonist on the opposite side of the joint, we easily 
see why it takes some time to learn to stand. 



APPENDIX TO CHAPTER IV. 

Many of the facts described in this chapter can be exhibited to a 
class with little trouble or expense. 

1. The sutures may be well seen on the skull of a rabbit or sheep. 
All that is necessary is to boil it thoroughly and then pick the bones 
clean, and wash out the brain. 

2. The structure of joints is easily exhibited on the fresh foot of a 
sheep or calf. On cutting open the joints the tough ligaments around 
them will be seen. The slippery synovial liquid covering the inside 
of the joint can be felt by the finger. The smooth gristle will be 
found to form a layer over the bones within the joint. A thin slice 
of it may be readily cut off with a knife, and its translucency, flexi- 
bility, and springiness exhibited. 

3. An example of a ball-and-socket joint may be easily obtained by 
cleaning the thigh- and hip-bones of a rabbit or chicken. 

4. For a good example of a hinge-joint the most easily available 
object is the skull of a dead cat. In this animal the lower jaw forms 
a perfect hinge-joint with the rest of the skull. 

5. The pivot- joint between atlas and axis can be demonstrated on 
the bones of a sheep's head and neck, after the piece of meat has 
done its duty at table. For this purpose buy mutton. The odon- 
toid process of a lamb is apt to separate. 

6. The form and structure of muscles can readily be exhibited on 
the hind leg of a frog. Place the animal for a few minutes in a cov- 
ered jar containing a pint of water to which has been added a tea- 
spoonful of ether. When the creature has become quite unconscious 
take it out, cut off its head, and run a stout pin down its back-bone 
to destroy the spinal cord. In this way all chance of giving pain is 
avoided. Then divide the skin at the top of each leg and pull it off. 
Point out especially the muscles between knee- and ankle-joints, and 
their long white tendons, many of them running to the toes. 

The leg of a chicken or turkey also affords an excellent object for 
examining tendons. The bellies of most of the muscles which move 
the toes lie in the part of the leg known as the ''drumstick." Their 
tendons run down the shank, and, if the skin be dissected off this, 
are readily found. Pulling some of the tendons bends the toes, pull- 
ing others straightens them; just as when they were pulled during 
life by the contracting bellies of the muscles in the drumstick. 

7. The nerve of a muscle can be easily shown on the calf-muscle 
of a frog's leg. Cut the tendon {tendo k chillis) which attaches this 
muscle to the heel. Then turn the muscle up, so as to expose its 
under side. Its nerve wiil be seen, as a slender white thread, enter- 
ing its deeper side a little way below the knee. 



CHAPTER V. 

CARE OF THE JOINTS AND MUSCLES. 

1. Dislocations and Sprains. — When we slip or stumble, 
some joint has to share with the bones the strain of our 
effort to recover our balance; or the weight of the body 
if we fall. Accidents to the joints are accordingly quite 
frequent, and it is important to know how to manage 
them until medical aid can be obtained. A sprain is an 
injury in which the ends of the bones remain in place 
but the ligaments are stretched or twisted or torn. In 
a dislocatioji^ the ligaments of the joint are torn, and 
the ends of the bones forced out of their proper posi- 
tions. 

2. How to Treat a Sprain. — The most important point is 
to give the joint complete rest. The injured ligaments 
become swollen and painful, and movement makes them 
worse. In the case of sprains of the finger and wrist the 
inflammation is often slight, and can be controlled by 
wrapping the joint in a moderately tight bandage for a 
few days, and keeping the arm in a sling so as to hinder it 
from being used. If the pain and swelling are great, the 
bandage should be kept wet with cold water. Sprains 

1. Why are accidents to the joints frequent? What is a sprain? 
A dislocation ? 

2. What does a sprained joint most require ? Why ? How may a 
slight sprain of a finger or wrist be treated? What should be done 
when a knee or ankle is sprained ? 



DISLOCA TIONS.—aO UT. 49 

of the knee and ankle joints are apt to be more serious, 
and if neglected or unwisely managed may lead to per- 
manent lameness. In such accidents it is best to send at 
once for a surgeon ; until he arrives, if the pain is great, 
apply cloths wrung out of hot water. 

3. What to do in Case of a Dislocation. — The ligaments 
and soft parts around dislocated joints swell rapidly, 
and make it not only difficult to find out in what direc- 
tion the bones have been displaced, but, after finding 
this, difficult to replace them. When a dislocation is 
suspected, get skilled advice as soon as possible; mean- 
time keep the joint at rest. More harm than good is 
almost certain to be done by the twisting and pulling 
and pushing of persons ignorant of anatomy. 

A dislocated finger may, however, be in most cases 
safely reduced — that is, have the bones put into place — by 
almost any one. What is needed is a strong pull, com- 
bined with pressure near the joint. The reduction of a 
dislocated thumb should never be attempted except by a 
surgeon. 

4. Gout is a disease in which some joints, usually of 
the toes or fingers, become red, swollen, painful, and 
very tender. Gritty matter also accumulates in them, 
making the cartilage rough and the joint stiff. In nine 
cases out of ten gout is due to indolent and luxurious 
habits, too little exercise, too much animal food, and, 
above all, indulgence in alcoholic drinks. The disease, 
like many others produced by alcohol, tends to be in- 
herited, and so some persons suffer from gout through 

3. Why should a surgeon be called at once in case of most disloca- 
tions ? How may a dislocated finger be usually reduced? 

4. What is gout ? To what often due ? What is said concerning 
hereditary gout ? Is gout ever fatal ? 



50 RHEUMATISM, 

the fault of a parent; overwork may bring on an attack 
in such. Even those born with a gouty tendency may, 
however, usually escape if careful in their habits. 

Gout is not merely painful but dangerous. It often 
attacks the heart, causing sudden death. 

5. Rheumatism is a name given to different diseases. 
In rheumatism of the joints^ or rheumatic fever ^ the liga- 
ments of most of the joints of the body are swollen and 
inflamed. The inflammation often attacks also the con- 
nective tissue outside or inside the heart (see Chap. 
XV.), sometimes leaving incurable heart-disease when 
the rheumatism itself has gone. 

The most common cause of rheumatic fever is pro- 
longed exposure of the skin, especially if it be hot and 
perspiring, to chilling while the body is at rest. There- 
fore, when warm, especially avoid sitting in a draught. 
Exposure to cold air when exercising, or a plunge 
into cold water for a few minutes' swim, will not cause 
the disease; but sitting still in a current of air or in 
wet clothes, or sleeping in damp sheets, is apt to do so. 

It is also well to know that rheumatic fever is more 
common, and more apt to cause heart-disease, in young 
persons than in old. 

Chronic ox permanent rheufnatism may attack either the 
joints or the muscles. It makes the joints stiff, painful, 
and finally useless. The most frequent form of chronic 
rheumatism of the muscles is Iwnbago, in which the lum- 
bar muscles in the lower part of the back are affected. 
Exposure to cold and wet is. its most common cause; but 

5. How are the joints affected in rheumatic fever? The heart? 
How is this disease commonly produced ? Why specially dangerous 
to the young? What parts does chronic rheumatism attack? Its 
effects on the joints ? What is lumbago ? Usual causes ? 



HYGIENE OF MUSCLES, %1 

the tendency to acquire it is much promoted by indul- 
gence in alcoholic drinks. 

6. The Importance of keeping our Muscles in Good 
Working Condition. — Man's mind is more than his body, 
but the mind turns its thoughts into deeds by means of 
the voluntary muscles. The better their state, the more 
promptly do they obey its commands; while a feeble or 
sluggish set of muscles will often bring to naught the 
best-laid plans of the mind. 

Mind without the power of directing movement, would 
be a source rather of pain than pleasure. Muscles un- 
guided by mind would make but a piece of machinery, as 
incapable of enjoyment as a steam-engine. Between 
these extremes, there lies a combination of vigorous well- 
trained brain and healthy active muscle, which is the 
highest condition of bodily welfare. 

7. Hygiene of the Muscles. — Every time a muscle is 
worked, some of its substance is used up and turned into 
waste matters. Nourishment must therefore be brought 
to the muscle, that new substance be formed instead of 
that destroyed; and the waste matters, which would 
poison the muscle if they were allowed to collect, must 
be removed. Both of these things are done by the blood : 
and the blood must be kept in good condition by nour- 
ishing food and pure air, if the muscles are to be healthy 
and vigorous. No article of dress should press tightly on 
any muscle; if it does it will hinder a free flow of blood 
in it and interfere with its proper nourishment. 

6. Why would our minds be of little use without our muscles ? 
What is the highest condition of bodily welfare ? 

7. What happens to some of its substance when a muscle is used? 
What follows from this? What part does the blood play in keeping 
the muscles in health ? What are necessary to keep the blood in 
proper condition ? How may a tight garment injure our muscles ? 



5^ EXERCISE, 

8. Exercise.— After good air and food the most im- 
portant condition for keeping the muscles healthy is 
that they be used regularly, or exercised, A muscle left in 
idleness dwindles in size and becomes worse in quality: 
instead of being hard, firm, and ready to contract, it be- 
comes soft, flabby, and feeble. This fact is well shown 
in the muscles of an arm or leg which has been kept mo- 
tionless for a few weeks while a broken bone is healing. 
When the bandages and splints are taken off, the mus- 
cles are nearly powerless, and much smaller than those 
of the opposite limb, which have been kept in use. 
Only by careful continued exercise, do they regain their 
former size and strength. The opposite fact, that mus- 
cles when used grow bigger and become more powerful, 
is illustrated by the huge " brawny" arm of a blacksmith. 

9. Too Much Exercise is as Harmful as too Little. — When 
a muscle is at work, it is used up faster than new muscle- 
substance is made; also, waste substances are produced 
faster than the blood can carry them off. After a time, 
this causes a feeling of being tired, which is Nature's 
signal that it is time to rest. To exercise until we are a 
little tired, does no harm; indeed, rather benefits than 
hurts the muscles, if followed by proper repose. During 
a time of rest following moderate work, more blood than 
usual flows to the muscle, conveying more nourishment 
than is needed for its repair; and so it grows larger and 

8. After good food and air what is next in importance for our mus- 
cles ? How does continued idleness affect them ? Illustrate. Give an 
example of the improvement of muscles by exercise. 

g. Why do we feel tired after hard muscular work ? What happens 
when we rest our muscles after moderate fatigue ? How does repeated 
overwork affect the muscles ? The body in general ? What is neces- 
sary for healthy muscles ? How is this illustrated by the heart ? The 
breathing muscles ? 



EXERCISE, 53 

Stronger. Frequent exercise carried on to the point of 
great fatigue, leads to wasting away and weakness of the 
muscles as surely as does continued idleness. It also 
enfeebles the whole body and makes it more liable to 
many diseases. 

Action and repose in turn, and neither in excess, are the 
conditions necessary for healthy muscles. In those whose 
action we cannot control b}^ the will, we find this illus- 
trated. The heart is a muscle which contracts seventy 
times or more every minute, in its w^ork of pumping the 
blood all over the body. Yet the heart beats on year 
after year and feels no fatigue. The secret of this is that 
after every contraction it rests before it makes the next 
one. The muscles which cause the movements of breath- 
ing, teach us the same lesson. If they stopped their work 
for five minutes, w^e should die for want of fresh air in 
our lungs. After each breath we draw, they take their 
rest, and so keep at work fifteen or sixteen times a min- 
ute all life long. 

10. The Proper Amount of Exercise is not the same 
for all persons. A strong healthy boy or girl runs about 
until pretty thoroughly tired, then goes home, eats a 
good supper, sleeps soundly, and wakes in the morning 
feeling all the better for the exercise. One who is deli- 
cate, should always rest as soon as the least fatigue is felt. 
Being delicate means, in most cases, that the organs of 
the body, the muscles along with the rest, only nourish 
themselves slowly; short exercise and long rest are there- 
fore necessary. If a person who is not strong becomes 

10. When should a delicate person stop exercising ? Why ? What 
is the result if a delicate person overexerts himself? How may- 
healthful games be made injurious ? What is about sufficient regu- 
lar exercise for a healthy adult of sedentary habits ? 



54 EXERCISE, 

greatly tired, he has little appetite, sleeps badly, and next 
morning still feels weary. His exercise, being more than 
his body is suited to bear, has done him harm. Many 
children (not to mention grown-up folks, who might be 
supposed to know better) run about in the excitement 
of some game, without realizing the fatigue, until after 
they have greatly overworked and injured their muscles. 
A walk of from six to seven miles daily is about the 
proper amount of exercise for a grov^^n person of ordi- 
nary strength, whose business is such as to keep him 
sitting most of the day and who is not able to take any 
other outdoor exercise. Horseback-riding is better for 
those who can afford it (p. 57). 

11. When to Exercise. — Severe muscular work causes, 
as we have learned, great muscular waste, and demands 
an abundant supply of nourishment for the repair of the 
muscles. For this reason, violent exercise should not be 
taken after a long fast. Strong vigorous young people 
may walk several miles before breakfast and not suffer in 
consequence, but others had better wait until after eating, 
before undertaking any great muscular exertion. Neither 
should exercise be taken immediately after a meal. At 
that time, a great deal of blood is needed in the stomach 
and intestines to help in digesting the food (Chap. XL); 
and it cannot be drained off to supply the muscles as it is 
during exercise, without risk of an attack of indigestion. 

12. Exercise should be Regular. — When we work our 
voluntary muscles, we give the heart and lungs more work 
to do. The heart has to pump more blood to the muscles, 

11. Why is it not wise to undertake hard muscular work when fast- 
ing? Just after eating ? 

12. How does n)uscular exercise affect the heart and lungs? What 



EXERCISE, 55 

\ 

and the lungs have to get rid of the extra waste matters 
(Chap. XIV.). You know that after running fifty yards 
at full speed, you find yourself breathing faster and your 
heart beating quicker. If you are used to such racing, 
you soon get your breath again, and your heart quiets 
down; for those organs, having been gradually trained to 
work just as your muscles need their help, do it easily and 
comfortably. But if a boy who is not used to running 
starts off on a fast race, he soon has to stop, panting for 
breath, feeling his overstrained heart thumping in his 
chest, and probably with ^' a stitch in his side." Exercise 
leading to such results does harm. A healthy boy usually 
gets all right again in half an hour or so; but quite often 
fatal disease of the heart has been caused, even in strong 
young persons, by prolonged violent exercise to which 
they were not accustomed. Girls have in several cases 
died in consequence of excessive exercise with the skip- 
ping-rope. Running to catch a train has often produced 
serious and lasting heart-disease in those who were weak 
or no longer young, and who were unused to such mus- 
cular exertion. 

An occasional long walk at a moderate rate, or leisurely 
rowing a boat for an hour or two, if followed by a good 
rest, will not injure any one in ordinary fair health: those 
whose pursuits confine them to a desk most days are 
usually benefited by such exercise once a week. But 
fast running, or foot-ball playing, or rowing a race, should 
never be undertaken by those who have not gradually 
educated their bodies to bear violent exercise. 

may you notice after running? What happens if a boy undertakes 
violent exercise without training? What organ is apt to be especially 
injured by unusual muscular exertion ? Why is it better to miss a train 
than race to catch it if you are not used to running ? 



$6 EXERCISE, 

13. Proper Exercise Benefits not only the Muscles but tlie 
whole Body. — Suitable exercise makes the heart do more 
work in pumping blood over the body, but not enough 
extra work to injure the heart itself; the consequence is 
a better nourishment of all the organs. Such exercise 
also makes us breathe faster and deeper and so bring 
more air into our lungs. If the air be pure and fresh, 
this also benefits all the organs. The muscles take their 
toll of the general beneficial results; but if their work is 
not excessive, a good deal of the profit is left for other 
organs. The digestive organs are put in better working 
state, appetite is increased and more food eaten and 
used; the skin and other organs concerned in getting 
rid of wastes, work better; the brain is better nourished; 
the mind clearer; and work which without exercise was 
laborious and wearisome becomes easy and agreeable. 

It is on these benefits to the body in general, which re- 
sult from proper exercise of the muscles, that the duty of 
taking such exercise mainly rests. It is not a particu- 
larly lofty ambition to be strong enough to knock down 
another man in a stand-up fight, though there may be 
occasions when such muscular strength is very desirable. 
In the long-run, the world is guided and ruled by vigor- 
ous minds more than by muscular bodies. Exercise, in 
promoting the general health of the body, piT)motes men- 
tal vigor; and when pursued not for its own sake or for 
mere athletic glory, tends to quicken the intellect, invig- 
orate the will, and strengthen character. Other things 
being equal, the healthy man or woman is the best in all 
the circumstances of life. 

13. How does proper muscular exercise benefit the whole body?. 
What is the chief reason which makes it a duty to take proper exercise ? 



EXERCISE, 57 

14. Varieties of Exercise. — In walking, the muscles 
chiefly employed are those of the lower limbs and trunk; 
the muscles of the arms are hardly used. Rowing and 
riding are better, since in them nearly all the muscles are 
exercised. No one exercise employs in equal proportion 
all the muscles, and gymnasia, in which different feats of 
agility are practised so as to call different muscles into 
action as may be desirable, have a deserved popularity. 
It should be borne in mind, however, that in the arms 
delicacy of movement is more important to many per- 
sons than great strength. The fact that gymnastics are 
usually practised indoors is also a great drawback to • 
their value. Out-of-door exercise in good or even mod- 
erate weather, is better than any other, and every one can 
at least take a walk. The daily *' constitutional " is, how- 
ever, very apt to become wearisome, and exercise loses 
half its value if unattended with feelings of mental re- 
laxation and pleasure. Active games, for this reason, 
have a great value for young and healthy persons; lawn- 
tennis, base-ball, and cricket are all attended with pleas- 
urable excitement, and are excellent also as exercising 
many muscles. 

15. We cannot profitably Work Hard with both Brain and 
Muscle. — Few persons can continue to put both body and 
mind to severe daily work without risk. Many a college 
student has completely broken down his health in the 
attempt. Every one should, however, regularly use both 

14, What muscles are left unexercised in walking ? Why are rovv- 
tng and riding better exercises ? Why are gymnasia useful ? What 
is the chief drawback to gymnastics ? Why are active games espe- 
cially valuable ? 

15. Why is it unwise for most persons to attempt to excel in both 
athletics and study ? What should every cne do? 



58 ACTION OF ALCOHOL ON MUSCLES, 

mind and muscle, doing his luork with one and simply 
exercising the other. Thus both are kept in health. 

16. The Action of Alcoholic Drinks on the Muscles. — In- 
dulgence in beers, wines, or spirits never does any good 
to the muscular system of a healthy person, and often 
does great harm. The injury may be direct or indirect; 
when indirect it is due to weakened will, impaired di- 
gestion, enfeebled heart, or disease of organs whose func- 
tion it is to carry waste matters away from the body. 
How alcohol leads to these consequences we shall study 
in following chapters. 

• The action of alcohol on the power of the muscles has 
often been carefully studied. Experiments prove that 
it is less on days in which spirits are taken (Chap. IX.). 

Continued indulgence in alcoholic drinks causes change 
for the worse in the structure of the muscles. The con- 
nective tissue and fat in them become too abundant and 
take the place of the proper muscular substance. This 
consequence is especially frequent in the muscular tissue 
of the heart (p. 162). 

16. How may alcoholic drinks indirectly harm the muscular sys- 
tem? What has been observed as to their direct action on muscular 
power? What changes in the structure of muscle are produced by 
continued alcoholic indulgence ? In what organ are they most* fre- 
■ quently observed ? 



CHAPTER VI. 

THE SKIN. 

1. The Skin is the tough pliable membrane which sur- 
rounds and protects the rest of the body. It is not 
tightly fixed to the parts beneath it, but can glide over 
them or be pinched up in a fold; as you may easily ob- 
serve on the back of your hand. The loose tissue which 
attaches the skin to parts under it contains a good deal 
of fat, except in very thin people; thus the form is made 
rounder and more beautiful than it would be if the skin 
fitted close to every bone or muscle beneath. This fat 
also serves as a soft padding or cushion protecting the 
deeper parts from injury by blows; and it checks loss of 
heat from the internal organs, by forming a sort of 
blanket around the body. In old age most of the fat is 
apt to disappear; the skin then falls into wrinkles, be- 
cause it is too loose to fit neatly; and extra clothing is 
required to keep in the heat of the body. 

2-. Structure of the Skin. — The skin is made of two very 
different layers. The inner layer is named the dermis^ 
and the outer the epidermis or cicticie. When your hand 
or foot becomes blistered in consequence of some exer- 

1. What is the nature of the skin? How is it attached to parts be- 
neath ? Point out some uses of the fat under the skin. Why are old 
people wrinkled ? 

2. What two layers compose the skin ? How is a blister produced? 



Co DERMIS AND EPIDERMIS. 

cise to which it is not accustomed, liquid collects between 
the cuticle and the dermis, causing the blister. 

3. What we may Learn from a Blistered Hand. — When 
you open a blister, you feel no pain when cutting 
through its outer covering; but if you touch the raw 
surface beneath, it smarts. This shows that the epider- 
mis has little or no feeling, while the dermis is very 
sensitive. You may also observe that when you cut 
through the cuticle, there is no bleeding; but if you 
gently prick with a pin-point the dermis under the 
blister, blood will flow. This shows that the dermis 
contains blood and the epidermis does not. 

4. Other Illustrations of the DiflFerence between the Der- 
mis and Epidermis. — Without waiting for a blister, you 
may readily learn the facts described in the preceding 
paragraph. Take a small needle threaded with fine silk, 
and, if you are careful not to go deep, you can em- 
broider a pattern on your hand without causing pain. or 
drawing blood. But if the point of the needle enters 
the dermis, you feel the prick, and a drop of blood is 
very likely to floAV from the wound. 

5. How the Epidermis is Shed and Renewed. — If you have 
ever seen an old brick house, you may have noticed that the 
bricks on the outside of the wall are worn away, crumbly, 
easily broken, and the mortar between them loose; while 
the bricks and mortar which lie deeper in the wall and 
have not been exposed to the weather, are perfectly 
sound. The epidermis (Fig. 21) is made up of millions 

3. How may we learn from a blister which layer of the skin is sen- 
sitive ? How discover which contains blood ? 

4. How may we in another way observe the same facts ? 

5. What might you notice on an old brick house? How do its 
walls resemble the epidermis ? Of what is the epidermis made up ? 



EPIDERMIS. 



6i 



of little pieces, called ce//s, joined together by a sort of 
glue. The cells may be compared to the bricks, and the 




i^^a 



Fig. 21. — A thin slice of epidermis, greatly mag-nified. a, the outer or horny layer 
of the epidermis, made of old dry cells; ^, the deeper moist layer of the epidermis, 
made of living growing cells; ci, the deepest row of epidermic cells, lying next the 
dermis; <:, the uppermost layer of the dermis; (it is seen to be elevated to form a 
papilla in which is a tuft of tubes, y, ^, containing blood;) /t, the duct of a sweat- 
gland. 

glue to the mortar, of a wall. Each cell is so small that 
a powerful microscope would be needed to see one by 



62 COMPLEXION, 

itself, but, cemented together in thousands, they make 
up the tough epidermis, as we see it covering a blister. 
The cells, a^ near the surface, exposed to the air and to 
wear and tear from rubbing against the clothes and 
other things, become different from the deeper cells, b. 
The outside part of the epidermis is in fact dead, and is 
being constantly shed and got rid of. Sometimes many 
cells come off together, as seen in the *^ peeling*' of the 
skin after an attack of measles, or in the rolls of matter 
which a rough towel rubs off after a warm bath. These 
outer cells make what is known as the horny layer of the 
epidermis. It may be compared to a very thin sheet 
of india-rubber covering the body. 

6. The deeper cells of the epidermis are kept moist 
and well nourished by a colorless liquid which exudes 
from the blood-vessels, /, ^, of the dermis beneath them. 
They grow and divide, and thus make new cells, which in 
turn are pushed to the outside to build the horny layer. 
Beneath a blister, some of the deepest epidermic cells 
remain sticking on the dermis. Being well nourished, 
they multiply very fast and soon restore the whole 
thickness of the cuticle, so that in two or three weeks no 
trace of the blister remains. 

7. The Complexion is due to the color of the deepest 
cells of the epidermis. In persons of blond or fair 
complexion, these cells contain very little dark coloring 

How is the outermost part of the epidermis worn away and renewed? 
What does a rough towel rub off the skin after a bath? To what may 
the outer layer of the epidermis be compared ? 

6. Describe the life-history of the deeper cells of the epidermis. 
How is the epidermis restored after it has been removed by a blister? 

7. How does the epidermis of a blond differ from that of a bru- 
nette ? How does sunlight affect the epidermis? Why is the scar of 
a deep wound white ? 



DERMIS, 63 

matter. In those of brunette or dark complexion, this 
pigment is more abundant. In negroes there is a large 
amount of it. 

Exposure to the air and to sunlight increases the quan- 
tity of coloring matter in the epidermis. Hence the 
skin darkens or *^ tans.'* If the whole thickness of the 
epidermis is destroyed, by a burn or wound, the deepest 
cells of the new epidermis do not usually form any color- 
ing matter; therefore scars remain white, even in negroes. 

8. Redness of the Skin and blushing are due not to 
changes in the epidermis, but in the dermis, which be- 
comes fuller of blood. The red blood is then seen 
through the epidermis. Constant pallor or great white- 
ness of the skin, is a sign that there is not enough blood 
flowing in the dermis; it is usually an indication of dis- 
ease. Some persons are pale from infancy and neverthe- 
less healthy; but they are exceptional. 

9. The Dermis consists of a close network of connec- 
tive tissue, containing in its meshes many nerves, and 
numerous tubes filled with blood, named blood-vessels. 
It is the nerves (Chap. XVII.) which give it feeling. 
When hides are tanned, the dermis is turned into leather. 
Its outer surface, next the epidermis, is not smooth, but 
presents numerous tiny projections, named papillcB, In 
Fig. 21 is* shown a papilla containing a knot of blood- 
vessels. Other papillae contain nerves instead of blood- 
vessels, and are concerned in the feeling of touch. On 
the palm of the hand, the papillae of the dermis are 

8. What is the cause of redness of the skin ? Of pallor ? Is con- 
stant pallor always a sign of disease ? 

9. Of what is the dermis composed ? What are its papillae ? What 
do different papillae contain ? How are the fine ridges and furrows of 
the palm produced ? What causes the deep lines of the palm ? 



64 ' THE NAILS, 

arranged in rows. The epidermis fills up the hollows 
between those of the same row, but dips down be- 
tween neighboring rows. In this way the fine ridges 
and furrows of the palm are produced. The deeper 
grooves of the palm, from whose size and course gyp- 
sies pretend to tell the fortune, have a different cause. 
They mark lines where the skin is most frequently 
folded in the movements of the hand, and where it is- 
more tightly tied down to the parts beneath it. 

10. Nails are made by a great development of the 
horny layer of the epidermis on the ends of the toes and 
fingers. This layer at these places becomes very thick, 
and grows out beyond the rest of the skin to form the 
edge of the nail. Our nails provide an armor to protect 
the tips of the tender fingers and toes, which are liable 
to many accidents. This protective use of the nail is 
well seen in Xh^hoof oi a horse or cow, which is but a 
thick nail. In beasts of prey, as cats and lions, the nails 
take the form of claws and are used in climbing and in 
catching prey. 

Each nail is nourished by the dermis beneath it, and at 
its root. If it be torn off, or be shed in consequence of a 
blow, it is reproduced, provided the dermis also has not 
been seriously injured. 

11. Hairs, long or short, coarse or fine, scanty or nu- 
merous, are found all over the skin except in a few 
places, as the palms of the hands and the soles of the 

10. Of what are nails made ? Use of ihe nails to man ? What is a 
hoof? A claw ? How are nails nourished? What is necessary in 
order that a '* cast" nail may be replaced ? 

11. On what parts of the skin are there no hairs ? What is a hair? 
What is the use of its papilla ? What is the follicle of a hair ? The 
root ? What are the uses of hairs ? 



HAIRS. 



65 



feet. A hair is a thread of epid 
top of a papilla of the dermis 
bottom of a tiny pit in the skin. 
On the papilla, new epidermic 
cells are produced as long as 
the hair continues to grow. 
When a hair is shed or pulled 
out, a new one grows in its 
place if the papilla has not 
been injured. The part of 
a hair which lies within its 
pit or follicle^ is known as its 
root. 

In many of the lower animals, 
hairs have an important use as 
clothing. In man the hair of 
the head may serve this pur- 
pose to some extent; it also 
aids in protecting the skull 
from injury. The eyelashes 
keep dust from falling into the 
eye; and the fine hairs over 
most of the surface drag on 
their roots when pushed and 
aid in the sense of touch. The 
papillae on which the hairs 
grow, are richly supplied with 
nerves. 

12. The Glands of the Skin.— 
the body have as their special 



ermis which grows on the 
(/, Fig. 22) placed at the 




Fig. 22. — ^The root of a hair, em- 
bedded in the pit of the skin in 
which it grew, a, stem of the hair, 
cut short; o, b, root of the hair; c, 
swollen end of the root which fits 
on the papilla of the dermis, /, 
which nourishes the hair; k^ k, 
openings of the ducts of oil-glands. 

Certain hollow organs of 
duty the preparation of 



12. What are glands ? A secretion ? A duct ? What glands pour 
their secretion on the skin ? 



66 



PERSPIRA TIOiV. 



peculiar liquids which they pass out through tubes. 
Such organs are cM^d gla?ids : the liquid which a gland 
collects or manufactures, is known as its secretion; and 
the tube through which the secretion is poured is named 
a duct. Two kinds of glands empty their 
secretion on the skin. They are the 
sweaty or sudoriparous^ glands^ and the oil^ 
or sebaceous, glands. 

13. The Sweat-Glands (Fig. 23) make 
the perspiration. They are very slender 
tubes which reach from the surface, 
through epidermis and dermis, to the 
fatty tissue beneath the skin. There the 
tube coils up into a knot. These glands 
are found all over the skin, but not 
equally distributed. In the palm of the 
hand there are nearly three thousand to 
each square inch: on the middle of the 
back, where they are fewest, about four 
hundred in the same space. There are 
in all about two and a half milliotis of 
sweat-glands, 

14. The Pergpiration or Sweat is a 
transparent colorless liquid, consisting 

mainly of water. Anything tending to heat the body 
causes perspiration to flow more freely, so its amount 
is very variable. On an average, it is at least two pounds 
daily. The sweat may dry up, or evaporate, as fast as it 




Fig. 23 —A sweat- 
gland, rt, horny lay- 
er of the cuticle; c, 
deeper layer of the 
cuticle; b, the der- 
mis. The duct of the 
gland is seen to run 
through the epider- 
mis and dermis and 
end in a coiled tnass 
priaced in the fatty 
tissue beneath the 
skin. 



13. Describe a sweat-gland. What is the number of these glands 
in a square inch of the palm ? Of the skin of the back? How many- 
are there altogether in the skin ? 

14. Describe the sweat. Why is it variable in amount ? What is 
its average quantity ? What is " insensible" perspiration ? Sensible ? 



OIL-GLANDS, 6y 

is poured out: then it is named insensible perspiration. 
When it is poured out faster than it evaporates, sweat 
collects in drops on the skin, and especially in regions, as 
the forehead, where the glands are very abundant. It is 
then named sensible perspiration. 

15. The Chief Use of the Sweat-Glands is to cool the 
body when there is danger of its becoming too hot. 
Whenever a liquid dries up or evaporates, it draws heat 
from whatever it lies on. Your saliva is warmer than 
the skin of your finger, but if, after wetting your finger 
with this warmer liquid, you expose it to the air it feels 
cool, because as the moisture dries up, it takes heat from 
the skin. Our bodies only work well when they have a 
temperature of about 98 degrees of an ordinary or Fah- 
renheit thermometer. If they get a little hotter than this, 
fever results, and many organs either cease to work, or 
work very badly. In health, the sweat-glands pour addi- 
tional liquid on the skin on a hot day, or when we are 
heated by exercise; and the heat taken away in the evapo- 
ration of this extra quantity of water, keeps the body 
cooled down to its proper temperature. When the body 
is cold the sweat-glands (except in disease) almost cease 
to make perspiration, and so loss of heat is checked. 

16. The Sebaceous or Oil Glands of the skin, pour their 
secretion into the sides of the pits in which the roots of 
the hairs are contained. The openings of the ducts of a 
pair of sebaceous glands are seen at k in Fig. 22. The 

15. What is the chief use of the sweat-glands? Explain. What is 
the proper temperature of the body ? If it become a little hotter what 
results? When do the sweat-glands secrete freely? When little? 
Why? 

16. Where do the sebaceous glands pour their secretion ? What are 
its uses? How do the sebaceous glands sometimes cause black spots 
in the skin ? 



68 SUMMARY, 

oily matter which they produce is partly spread over the 
hairs, and partly over the general surface of the skin. 
A healthy skin is always a little greasy, except on the 
palms of the hands and the soles of the feet, where there 
are no hairs and no oil-glands. This oily covering pre- 
vents the skin from absorbing water when the air is 
damp; and from drying up on a hot dry day. 

Sometimes the mouth of a sebaceous gland gets choked 
up, and then its secretion collects in it and becomes dark- 
colored. In this way little black specks are formed on 
the skin. They are most frequent on the nose, where 
the sebaceous glands are large, though the hairs to which 
they belong are very small. Pressure between the finger- 
nails will usually easily force out the collected secretion 
and remove the speck. 

17. Summary. — The skin forms a tough, elastic, protec- 
tive covering for the body, and is also the main organ 
of the sense of touch. 

It is loosely attached to parts below it, so that it can 
glide over them in our movements, without being 
stretched or torn. Beneath it is a cushion of fat which 
protects the muscles from injury by blows. 

Anotlier use of the fat beneath the skin is to check 
loss of heat from the body. Warm-blooded animals 
which live in the sea, as whales, have a very thick layer 
of fat, known as " blubber,'* under the skin. This 
enables them to retain their animal heat in spite of the 
cold water around them. For the same reason, a fat per- 
son can bathe longer in cold water without being chilled 
than one who is thin. 

17. Functions of the skin ? How attached to parts beneath ? Uses 
of the fat under the skin? Illustrate. Layers of the skin ? Characters 



SUMMARY. 69 

The skin consists of two layers. The outer or epidermis 
is not sensitive and contains no blood. The outer part of 
the epidermis is dry, horny, and dead. It is constantly 
being shed. ^^ JUt^^4^ €U 

The deeper layer of the epidermis is moist, and, being 
well nourished by liquid soaked up from the blood-ves- 
sels of the dermis, grows fast and makes new cells which 
are pushed on towards the surface to take the place of 
those of the outer layer which are shed or rubbed off. 

The dermis contains many nerves and much blood. 
An important use of the epidermis is to cover and pro- 
tect it. If there were no epidermis, our wiiole surface 
would feel like the "raw" skin at the bottom of a blister. 

Nails are made by great growth of the horny layer of 
the epidermis. Their function is protective. 

Hairs are scattered over nearly the whole skin. They 
are threads of epidermis developed from the bottom of 
little pits in the skin. When large and abundant, as on 
the head, they protect from cold and blows. Even when 
small and few, they are useful by aiding in the sense of 
touch. 

Glands are hollow organs which make special liquids. 
The liquid made by a gland is called a secretion^ and is 
poured out through a tube, the duct of the gland, on 
some surface outside or inside the body. The sweat- 
glands and the oil-glands pour their secretion on the 
skin. 

The sweat-glands are most active when the body is 
warm, and help to keep it at its proper temperature. 

of outer layer of epidermis? Deeper layer? Characters of dermis? 
How epidermis protects the dermis ? Nails ? Hairs ? Uses ? 
Glands? Secretions? Ducts? Glands of the skin? Use of sweat- 
glands ? Of oil-glands ? 



^0 SUMMARY, 

The oil-glands pour their secretion into the hair-folli. 
cles. They provide a sort of natural hair-oil. Their se- 
cretion, also, becomes spread over the skin and makes 
the cuticle slightly greasy, so that water tends to run off 
instead of soaking into it. 



CHAPTER VII. 
HYGIENE OF THE SKIN.— ANIMAL HEAT.— CLOTHING. 



1. Why the Skin should be Kept Clean. — A film tends 
to collect on the skin daily. This film consists chiefly of 
dry dead cells from the surface of the epidermis, of oily 
matter from the sebaceous secretion, and of dust and 
dirt. A certain amount of sebaceous secretion is useful 
for reasons already given; but it may collect in harmful 
excess. If the accumulation of the above-named matters 
is not regularly removed from the skin it tends to choke 
the mouths of the sweat-glands, the so-called "pores of 
the skin," and interfere with their activity. These glands 
not only serve to regulate the heat of the body, but sepa- 
rate waste matters from it, among them a considerable 
amount of water which has served its purpose and needs 
to be removed. If the sweat-glands do not work well, 
other organs, the lungs and kidneys, whose duty it also 
is to remove water and wastes, have too much work 
thrown upon them. The entire skin should therefore 
be washed every day, except that on the top of the head. 
The hair takes so long to dry that it is not usually prac- 

I. Of what is the film composed which collects on the skin every- 
day ? Why should it be removed ? What are the pores of the skin ? 
The uses of the sweat-glands? What organs are overworked when 
the sweat-glands do not act properly ? What other reasons are there 
for keeping the skin clean ? 



^2 BA THING, 

ticable to wash the head oftener than once or twice a 
week. 

No doubt many folk go about in very good health 
with very little washing; contact with the clothes and 
other external objects prevents any great collection of 
dirt or dead epidermis on the surface of the skin. But 
apart from the duty of personal cleanliness imposed on 
every one as a member of society in daily intercourse 
with others, the mere fact that the healthy body can 
manage to get along under unfavorable conditions is no 
reason for exposing it to them. The evil consequences 
may be experienced any day, when something else 
throws another extra strain on the already overworked 
lungs and kidneys. 

2. Bathing. — A bath not merely cleanses the skin but, 
when of the proper temperature and taken at the right 
time, strengthens and invigorates the whole body. For 
strong healthy persons, a cold bath is the best. When the 
water is very cold they may take the chill off, but should 
not make it warm. For the delicate, tepid baths may 
be preferable, but should be very brief. Immediately 
after a bath the skin should be dried and well rubbed. 

3. Effects of a Cold Bath.— The first effect of a cold 
bath is to drive blood from the skin and make it pale. 
This is soon followed by a reaction in which the skin 
becomes red and full of blood, and a pleasant glow of. 
warmth is felt in it. The proper time to come out of a 
cold bath is during this reaction. If the stay in the 
water be too long, the skin again becomes pale and blood- 

2. What useful purposes are served by bathing? Proper tempera- 
ture of bath ? What should be done immediately after bathing ? 

3. Why does a plunge in cold water make the skin pale ? What 
follows? When should one come out of a cold bath ? What are the 



COLD BATHS, 73 

less, and the person probably feels chilly, depressed, 
and uncomfortable for some hours. The bath has then 
done harm; it has weakened instead of bracing the system. 

How long one may remain in cold water with benefit, 
varies with the temperature of the water and with the 
vigor of the person. A strong man can set up a healtliy 
reaction after a much longer stay in the water than can 
a feeble one. Also a person used to cold bathing may 
w^ith safety continue his dip longer than one unaccus- 
tomed to it. Many persons who have been taking warm 
or tepid baths all the rest of the year, injure themselves 
in the summer by commencing at once to bathe for 
twenty minutes or more in the sea. Such persons com- 
plain that sea-bathing does not agree with them; if they 
would begin with three or four minutes in the water, the 
first day, and gradually increase the time, they would in 
most cases be benefited. 

4. When to Bathe. — It is perfectly safe for a healthy per- 
son to take a cold bath when warm, provided the skin is 
not perspiring profusely. On the other hand, never take 
a cold bath when you are feeling chilly; or when you are 
much fatigued either in mind or body. Under such cir- 
cumstances, the proper reaction is apt not to occur. A 
cold bath should not be taken soon after a meal, for the 
blood is then wanted in the digestive organs (Chap. XL) 
and cannot be spared to the skin to set up the after-glow. 
For a brief daily dip, there is no time so good as imme- 
diately after rising, while the body is still warm from 
bed and in a rested vigorous condition. 

consequences of staying too long in it? State the conditions which 
determine the length of time it is wise to bathe in cold water. 

4. When is it safe to take a cold bath? When iinwise? What are 
tb^ be?t times for bathing ? 



74 WARM BATHS, 

5. Shower-Baths take less heat from the body than 
other cold baths. The falling water also stimulates the 
skin and aids in producing the after-glow. Hence 
shower-baths are valuable to those not in very good 
health, provided they suffer no unfavorable reaction. But 
the sudden shock is unfavorable to many people; es- 
pecially to those having any difficulty with the heart. 
Persons with whom they agree, frequently find it advan- 
tageous to stand with the feet in tepid or warm water 
while taking a shower-bath, and to keep the head covered 
by an oilskin cap. They thus avoid headaches and cold 
feet, while getting the general benefit of the bath, 

6. Warm Baths cleanse the skin more readily than 
cold, and are desirable once or twice a week for this 
purpose. Daily warm baths should not be taken except 
on medical advice. While promoting the tendency to 
perspiration, w^hich is often important in the treatment 
of disease, they also, when frequent, diminish the general 
vigor of the body. 

7. The Use and Abuse of Soap. — Nearly all soaps con- 
tain so much potash or soda that lathers made from 
them are really weak ^' lye." On this their main cleans- 
ing power depends; for, like the lye used to remove 
stains from floors, they take up greasy matters and 
make them capable of being washed away by water. 
The potash or soda of soap often does harm, causing too 
free removal of the oily sebaceous secretion, a thin layer 
of which is necessary to protect the skin from too rapid 

5. In what circumstances are shower-baths desirable? What pre- 
cautions should delicate persons observe in taking them ? 

6. What are the uses of warm baths? Their dangers ? 

7. What makes soap cleansing? How may it injure the skin? 
How should its use be limited ? Name a good substitute for soap. 



COSMETICS, 75 

drying. Probably as many skin-diseases have been 
caused by too free use of soap, as by uncleanliness. Ex- 
cept on parts of the body especially exposed to contami- 
nation, soap should not be applied oftener than twice a 
week. More frequent employment of it is quite un- 
necessary for cleanliness, if a daily bath, followed by a 
good rubbing with the towel, be taken. Persons whose 
skin is injured by even the occasional use of soap, will 
find in corn-meal a good substitute. 

8. Cosmetics and Hair-Dyes. — When the face is hot 
and perspiring, a good deal of comfort may often be ob- 
tained by applying a little finely powdered arrowroot, 
and immediately wiping it off with a dry towel. This 
is better than plunging the face in water, which often 
causes it to become more flushed afterw^ards. No face- 
wash, whitening, rouge, or other coloring matter should 
ever be used. In spite of the assertions of their makers, 
which induce foolish folks to buy them, nearly every 
one contains materials highly injurious to the skin. 
Those which do not, are hurtful by interfering with the 
proper growth of the epidermis and by checking the 
action of the sweat-glands. Many face-washes contain 
poisons which, being absorbed by the skin, ruin the 
health. 

Most hair-dyes contain lead or some other poison. As 
they are kept off the skin as much as possible, they do 
not in most cases injure it, but they always harm the 
hair, never improve its appearance, and seldom succeed 
in their purpose of deceit. 



8. State a harmless method of quickly cooHnq: a heated fare. Whv 
should face-washes and oth^r "cosmetics" be avoided? Why hair- 
dyes ? 



J^ ACTION OF ALCOHOL ON THE SICIN 

9. Burns and Scalds.— If slight, cloths soaked in strong 
solution of bicarbonate of soda (common washing or 
cooking soda) may be applied, and renewed when they 
begin to dry. This greatly relieves the pain. If the 
burn or scald be deep and extensive, endeavor to exclude 
the air and prevent rubbing until medical aid can be ob- 
tained. The best application for these purposes, is raw 
cotton soaked in a mixture of linseed-oil and lime-water 
in equal parts. If this is not at hand (as it should be 
in every house distant from a drugstore), sweet-oil or 
fresh lard may be used instead. 

10. Action of Alcoholic Drinks on the Skin. — Taken into 
the body in any form, alcohol causes more blood to 
flow to the skin. This is seen in the flushed face of a 
man who has been ^' drinking." If the drinking be con- 
tinued, the redness becomes permanent. The skin is 
then puffy and congested, and the face especially ac- 
quires a reddish blotchy look. Its proper nourishment 
being interfered with, the epidermis collects in scaly 
masses. The peculiar degraded look of the sot's face is 
the result. 

11. Animal Heat. — Sometimes you feel hot, sometimes 
cold. This feeling is due to changes in your skin. The 
mouth may feel hot after drinking a cup of tea, or cold 
for a short time after eating ice-cream: but this does 
not make us say that we, that is our bodies in general, 
feel warm or cold. 

9. What handy remedy is useful for slight burns ? What should be 
done in case of severe burns or scalds ? 

10. How does " drinking" affect the skin ? The expression ? 

11. To what are "feeling hot" and "feeling cold" due? Illus- 
trate. What is *' animal heat" ? 



TEMPERATURE OF THE BODY, 77 

If you keep your mouth closed, your tongue does no 
feel warm on a hot day, or cold when the air around you 
is at a freezing temperature. The reason of this is that 
in your body heat is being produced all the time, keep- 
ing the internal parts warm. This heat is known as aiti- 
Dial heat. 

12. The Temperature of the Body. — So long as you are 
in health, a thermometer placed in your mouth would 
indicate almost exactly the same temperature every day 
in the year. This is a very curious fact. A stone or a 
frog is cold on a cold day and warm on a hot day; but, 
except sometimes on the outside, your body is always 
hot, and hot to very nearly the same degree; in health 
never below 98"^ or above 101° of an ordinary Fahrenheit 
thermometer. All animals, as birds and beasts, which, 
like man, have a regular temperature of their own, are 
known as "warm-blooded" animals. Any condition of 
the body in which its organs are hotter than their proper 
temperature, is known as a "fever." 

13. How the Body is kept from getting too Hot. — Every- 
thing that works, even two sticks rubbed across each 
other, produces heat, though in many cases it is too slight 
to be noticed. The organs of our bodies are no excep- 
tion; and the more they work, the more heat they pro- 
duce. If all this heat remained in the body, we should 
soon be in a high fever. It is carried oif in several ways. 

12. What does a thermometer placed in the mouth show ? How 
does your body differ as to temperature from a stone or a frog ? 
What is the healthy temperature of the interior of the human body ? 
What is meant by ** warm-blooded animals" ? What is fever? 

13. Where is heat produced in the body ? When most ? Why must 
some of it be got rid of ? How do the lungs help in keeping us from 
becoming too warm ? The sweat-glands ? The blood flowing tbrougli 
the skin ? 



78 REGULATIOX OF BODILY TEMPERATURE, 

Partly, for example, by the air we breathe oat, which is 
nearly always hotter than the air we breathe in: and so 
carries heat away from the body. But the skin does 
more than any other organ in regulating the bodily 
temperature. 

The skin gets rid of the heat in two ways. In the first 
place, its glands produce perspiration, and the evapora- 
tion of this perspiration, as we have already learned, 
carries off heat (p. 67). We thus see why it is useful that 
we perspire more freely on a hot day, or when we are ex- 
ercising and our muscles producing a great deal of heat. 

In the second place, except on the very hottest sum- 
mer days, the air around us is cooler than the inside of 
our bodies. Blood which has been made hot as it 
flowed through the internal organs, is sent to the skin 
and there, giving heat to the air, is cooled. It is then 
carried back from the skin to the inside, picks up more 
heat, flows again to the surface and gets rid of it; and 
so on, all the time. 

14. How the Body is kept from getting too Cold. — The 
fat which lies beneath the skin may be compared to the 
packing in the sides of a refrigerator. It checks the pas- 
sage of external heat or cold to the inside. Accordingly, 
thin persons cannot bear exposure to cold as well as 
those who are fat. Too great loss of heat is also pre- 
vented by the diminished activity of the sweat-glands in 
cold weather, and by the fact that most of the blood is 
then kept away from the skin, which accordingly becomes 
pale. An exception to this is found when there has been 

14. How does fat aid in keeping us from too great cooling ? How 
do the sweat-glands behave in cold weather? Why does the skin 
usually become pale in a cold room? When may the skin be red 

and perspiring even in cold weather ? 



CLOTHING, 79 

great production of heat in the internal organs. Then 
the sweat-glands act, and the skin becomes full of blood 
even on a winter's day. You know that if you sit still 
in a cold room your skin becomes pale and you do not 
perspire; while, so long as you are in health, a good run 
in the coldest weather will flush the skin and cause per- 
spiration. 

15. Clothing. — Clothes are employed by mankind for 
many purposes of ornament and ostentation; and these 
unimportant uses are sometimes allow^ed to interfere 
very seriously with their main objects. The real uses of 
clothing are physiological and hygienic. These uses are, 
(i) to aid the skin in regulating the temperature of the 
body; (2) to protect the skin itself from too rapid heat- 
ing or cooling; (3) to prevent a sudden rush of blood 
from the skin to internal organs when the air around the 
body is quickly cooled. 

16. What Properties the Materials used for Clothing 
should Possess. — Nature has provided all warm-blooded 
animals who thrive in parts of the earth where the 
climate is variable, except man, with a covering of fur or 
feathers. This covering becomes thicker in the cold 
seasons of the year, and thinner in the w^arm. It also is 
made of materials which greatly hinder the passage of 
heat through them. Fur and feathers are accordingly 
known as bad conductors of heat. In winter they check 



15. For what unimportant uses is clothing employed ? What its 
real uses ? 

16. What clothing does Nature provide for most warm-blooded 
animals? How does it change with the seasons? What are the prop- 
erties of its materials as regards the transmission of heat ? How dc 
fur and feaihers protect the skin from sudden changes of tempera- 
ture ? What lessons should man learn from the clothing provided 
for lower animals by Nature ? 



§0 CL O THIKC MA TEkIA L S. 

loss of heat from the skin; and all the year round they 
keep the skin from being rapidly cooled or heated when 
exposed to sudden changes in temperature. 

Man has to provide his own clothing, but should al- 
ways bear in mind this lesson from Nature: His cloth- 
ing should vary in amount with the season, but the chief 
garments should be made of materials which are bad 
heat-conductors. 

17. The Relative Value of various Clothing Materials. — 

Furs are very bad conductors, and do not easily be- 
come damp. They are the most suitable clothing for 
very cold weather. Woolle7i fabrics are also excellent. 
Silk comes after wool, and in our variable climate forms 
the best material for the underclothing of those whose 
skins are irritated by woollen materials, such as merino. 
Cotton is not so good as silk, but is far better than litien, 
which not only allows heat or cold to pass readily 
through it, but easily absorbs moisture and becomes 
damp. The same objection holds against linen bed- 
clothing. Cotton should be used, except, perhaps, for 
pillow-cases in summer. 

The proper clothing will vary with climate and sea- 
son; but, except for those living in regions where sudden 
temperature-changes do not occur, the following is the 
proper rule: Wear silk or wool next the skin; over 
this regulate the amount of clothing according to the 
weather, but always wear at least one other covering of 
non-conducting material, cloth, silk, or flannel. 



17. Name common materials for clothing in order, putting the 
worst conductors of heat first. Why is linen not so good a clothing 
material as cotton? What rule as to clothing should be observed by 
all who live in a variable climate ? 



CHAPTER VIII. 
FOODS. 

1. How the Body is Built up and Repaired. — So long as 
you are growing, you require a supply of material out of 
which your body can make more bone and muscle and 
skin and blood, and the rest. This material is supplied 
in the things you eat and drink. 

Even after a man is full-grown, he still needs a quan- 
tity of food daily, to repair his body. Every time an or- 
gan works, some of it is used up and turned into useless 
waste things, w^hich are soon carried away from the body 
through the pores and other outlets. If they are kept 
in it, as they sometimes are in disease, they clog all the 
organs and interfere with their work. If a man be starved, 
he becomes lighter every day, because he makes waste 
matters, and these are carried away by the skin -or the 
lungs (Chap. XIV.) or the kidneys (Chap. XVI.) or other 
organs, all the time so long as he lives. 

2. The First Use of Foods is, then, to furnish materials 
for the building and repair of the body. In early life, 
the building exceeds the waste, and growth takes place. 



1. What does the body require while growing? How supplied? 
Why does a full-grown man need food ? Why must the wastes of the 
body be removed ? Why does a man become lighter if he takes no 
food ? 

2. What is the first use of foods ? Why do we grow while young ? 
Why not in middle age ? What often happens in old age ? 



82 oxiDA Ttoisr. 

Then comes a period of middle life, in which they are 
about equal. Finally, in old age, it often happens that 
the organs cannot make use of enough food for their 
complete repair, and therefore slowly diminish in size. 
The muscles and bone of an old man often become 
^^ wasted" and feeble. 

3. A Second Use of Foods is to give us strength and 
keep up our animal heat. A starving man not only be- 
comes lighter every day, but weaker and colder. This 
use of foods may be compared to the use of coal in the 
furnace of a steam-engine. And just as the coal would 
be useless if it did not burn, and will not burn unless 
there be a draught of air in the furnace, so foods would 
neither make us strong nor warm did they not contain 
things which could very gently burn inside the body; 
and in order to burn, these things must be supplied with 
air by our breathing. 

4. Oxidation. — The air which we breathe into our 
bodies is a mixture of two gases; only one of them is 
useful in keeping a fire alight or in burning foods 
inside our bodies. It is named oxygen. Generally 
when anything burns, it unites with oxygen. The 
thing burned is then said to be oxidized^ and the process 
of uniting with oxygen is named oxidation. When oxi- 
dation takes place very fast, a great deal of heat is given 
out along with light, as in a fire or candle. But oxida- 
tion sometimes goes on slowly; and then the tempera- 

3. What is the second use of foods ? How shown ? To what may 
the use of foods be compared ? In order that a fire may burn what is 
necessary besides coal or wood ? What must food contain ? What 
is necessary that these things may burn ? How is it supplied ? 

4. What is oxygen ? When is anything said to be oxidized ? What 
is oxidation ? What are the effects of rapid oxidation? Of slow? 
Which kind of oxidations occurs in our bodies ? Why ? 



DEPWITION OP FOODS. 83 

ture does not become very high and no light is produced. 
The oxidations which take place in our bodies, are of 
course slow oxidations; otherwise they would burn us 
to ashes. 

5. Examples of Slow Oxidation. — A good example of a 
slow oxidation is afforded by the rusting of iron; this is 
an oxidation; and the rust is iron united with oxygen. 
This oxidation usually occurs even more slowly than 
those which take place in our bodies, and so heat is 
given off so slowly that rusting iron does not feel warm 
when we touch it. You know, too, that iron rusts easily 
in damp air, and in this respect the oxidation of the iron 
is like the oxidations which occur inside our bodies, 
which are moist in every part. 

6. Definition of Foods. — Foods include all substances, ex- 
cept air, take 71 into the body and serving for any one of three 
purposes — (i) to provide material for its growth or repair, or 
(2), by their oxidation, to supply it with zvorking power or to 
keep it warm, or (3) to aid in carrying nourishment from 
part to part. To the above, we must add that for a sub- 
stance to be properly a food, neither itself nor anything 
produced from it inside the body shall be injurious to the 
structure or action of any organ; otherwise it would be a 
poison, not a food. 

Most foods serve more than one purpose. Thus meat 
and bread furnish material for growth and repair, and 
also supply strength and warmth. Water is found in all 
the organs, and is a necessary part of them; but it also 

5. Give an example of slow oxidation. In what other respect does 
the rusting of iron resemble the oxidations which take place in our 
bodies ? 

6. Define foods. Poisons. What purposes are served by meat 
and bread ? By water ? Illustrate. 



84 NOURISHING SUBSTANCES OF FOODS. 

dissolves solid foods and carries them into the blood 
to be conveyed to places where they are needed. A 
lump of sugar in your mouth would not nourish you, 
unless the saliva should dissolve it, and then it should 
be taken up into the blood and borne to muscle or brain 
or skin, or some other part that wanted new material. 

7. Classification of Foods. — Foods, like the body itself, 
consist of both things which will not burn or oxidize, and 
things which will. The food-materials which will not 
burn, such as water and common salt, are known as in- 
organic foods. The foods which will burn, are obtained 
either from animals or plants, and are named organic 
foods^ because they are obtained from living things, 
which have orga?ts. 

8. Most Foods contain more than one Nourishing Sub- 
stance. — Beef, for example, contains (i) water, which 
goes off when we dry it; (2) certain minerals, which are 
left in the ashes if the meat be burned, and which, when 
meat is eaten, are useful in building bone, blood, muscle, 
and brain; (3) organic matters of several kinds: the fat 
is one of them; another, found in the lean, is named an 
albumen. It is in nearly all respects like the white of an 
egg. To take another example, wheaten bread contains 
(i) some water; (2) minerals; (3) a kind of albumen; 
(4) starch; (5) a little fatty matter. Each nourishing 
substance found in any food, is named 2^ food-stuff . 

9. The Chief Kinds of Organic Food-Stuffs are — (i) albu- 



7. Of what do foods consist ? What are inorganic foods ? Examples. 
Organic ? From what obtained ? Why so named ? 

8. What substances, useful to the body, does meat contain ? What 
does the albumen resemble? What are the useful substances in 
bread? What is a food stuff ? 

9. Name the chief organic food stuffs. 



INORGANIC FOOD-SrUFFS, 85 

mens; (2) jelly-forming substances; (3) fatty or oily 
matters; (4) sugars; (5) starch. The albumens are the 
most important. A man can maintain life on water and 
lean meat, while if he should get, along with plenty of 
water, all the fat and sugar and arrowroot (which is 
nearly pure starch) that he could eat, he would slowly 
starve. 

The reason of this is very simple. A special substance, 
named nitrogen^ is essential for the making or repairing 
of all the organs of the body. Albumens contain some 
of this substance; fat, starch, and sugar do not. Every 
day some nitrogen is carried away from the body in its 
waste matters. If none of it be supplied in the food, a 
man will therefore slowly die of nitrogen-starvation, no 
matter what abundance he may have of other things. 

Crackers and cheese would be useless to a man dying 
of thirst; so fat or sugar or starch would be useless to a 
man whose organs were starving for nitrogen. 

10. Inorganic Food-Stuffs. — A sufficient quantity of 
most of these is contained in bread and meat and milk 
and our other common foods. Thus iron is an essential 
part of the blood, but in health we need no more than 
is contained in the vegetables and meat which we eat 
daily. 

Water and common salt are the only inorganic food- 
stuffs that are usually taken by themselves or specially 
added to our food in cooking. The body daily gives 
off more of each than it would otherwise receive. 

Which are the most important? How do we know that the others 
are less valuable ? Explain why starch and fat cannot take the place 
of albumens in nourishing the body. Illustrate. 

10. How are we supplied with most inorganic food-stuffs in suffi- 
cient quantity ? Illustrate. How are water c|.nd common salt excep- 
tional ? Why ? 



86 SA L T. —ME A TS. —MILK. 

11. Common Salt is found in every solid part and every 
liquid of the body. It has been maintained that salt as 
a separate article of diet is a mere luxury, and there 
seems to be some evidence that certain savage tribes live 
without more than they get in the meat and vegetables 
wliich they eat. There is, however, no doubt that to 
many animals, as well as most men, the want of salt 
is a terrible deprivation. Buffaloes and other crea- 
tures are well known to travel miles to reach " salt- 
licks;" of two sets of oxen, one allowed free access 
to salt, and the other given none save what exists in 
their ordinary food, it was found after a few weeks that 
the former were in much better condition. In man the 
desire for salt is so great that in regions where it is 
scarce, it is used as money. In some parts of Africa, a 
small quantity of salt will buy a slave, and to say that a 
man commonly uses salt at his meals, is equivalent to 
stating that he is a luxurious millionaire. 

12. Meats, whether derived from bird, beast, or fish, 
are highly valuable foods. They supply material for 
making tissues, for providing working power, and for 
keeping up animal heat. 

13. Milk will support life longer than any other single 
food. It contains water, minerals, a kind of albumen 
named casei?i, which, when separated, forms cheese; fatty 
matters, especially butter; and a sugar named 7?itlk-sugar, 
In milk there is more lime than any other common 
food; it is. therefore very valuable in childhood when 
the bones are growing rapidly. 

11. In what parts of the body is common salt found ? What is said 
to result from want of it ? Illustrate the natural longing for salt? 

12. What is said of the value of meats ? 

13. Why is milk a very valuable food? Name the chief food-stuffs 
contained in it. Why is it especially valuable in childhood ? 



EGGS.— BREAD.— VEGETABLES AND FRUITS. 87 

14. Eggs are rich in albumen and fats. They contain 
a great deal of valuable nourishment in a small bulk. 
The white, or albumen, is more easily digested when 
cooked soft, and the yolk when cooked hard. So in 
the old controversy about hard-boiled and soft-boiled 
eggs, as in a good many controversies, both sides are 
wrong and both sides are right. 

15. Bread made from wheaten flour is more nourishing 
than any other, as it contains, besides much starch and 
a little sugar and fat, a good deal of a kind of albumen 
named gluten. In preparing ordinary white flour, the 
husk of each grain of wheat is sifted out by a process 
known as bolting. This husk contains a good deal of 
nourishing matter. In unbolted flour this is saved. 
Many persons also find bread made from it more whole- 
some than that made of bolted flour. In other cases it 
unduly irritates the bowels. Maize or corn contains more 
starch and fats than wheat, but much less albumen. 

16. Vegetables and Fruits. — Rice contains a great deal 
of starch but hardly any albumen: by itself it is a very 
poor food, but taken with food rich in albumen, as meat 
of any kind, it is excellent. Peas and beans are good 
foods: they contain much albumen and starch. Potatoes 
are a poor food. Other fresh vegetables, as cabbage, tur- 
nips^ and tomatoes, are useful mainly for the mineral mat- 
ters contained in them. Most of their weight is due 

14. What do eggs contain ? When are they more easily digested ? 

15. What is the most nourishing kind of bread? Why? What 
is meant by the "bolting" of flour ? What is saved when flour is un- 
bolted ? What is said of the healthfulness of eating bread made from 
unbolted flour? How does corn differ in composition from wheat? 

16. What is said of rice ? Of peas and beans ? Potatoes ? Other 
fresh vegetables? What is their chief constituent ? What is said of 
fruits ? Give proof of their value. 



88 JELLY, 

simply to water; organic food-stuffs are present in them 
in very small quantity. Fruits^ like most fresh vegeta- 
bles, are chiefly valuable for their mineral matters. Some 
kind of fruit or vegetable is, nevertheless, an important 
part of every one's diet. This is shown by the fact that 
sailors on a long voyage almost invariably suffered from 
the disease known as scurvy] before the '^ canning" of 
vegetables and fruits made it possible to keep the crew 
supplied with them. 

17. Jelly. — Jellies made from animal substances, as 
calves* feet, or the gelatin sold in groceries, are com- 
monly believed to be extremely nutritious. It is there- 
fore important to know that, although they contain 
nitrogen, they cannot entirely take the place of albu- 
mens. When our bodies are supplied with animal jelly, 
they can manage to get along with less albuminous food, 
but the organs need for their growth or complete repair, 
food containing some albumen. If a sick person can 
digest some lean beefsteak, it is more valuable as a food 
than the best calf's-foot jelly; but if he can only digest 
the jelly it is very useful, because, though it does not 
entirely prevent the loss of nitrogen from the body, it 
considerably lessens it. 

18. The Cooking of Meats, in many cases causes special 
flavoring matters to be formed, which make our food 
more palatable. In addition it makes many foods more 
digestible. 

When meats are properly cooked they become softer 

17. What jellies are usually supposed to be very nourishing? 
What is it important to know about them ? How and when may they 

be very useful ? 

18. How does cooking make meats more pleasant to the taste ? 



COOKING, 89 

and more easily broken up by the teeth because their 
connective tissue loses its toughness, being for the most 
part turned into jelly. If the meat be cooked too fast 
this change occurs very imperfectly, and it comes to 
table stringy, tough, unpleasant to eat, and hard to di- 
gest. 

When meat is boiled, much of its flavoring and some of 
its nourishing matters are apt to pass out into the water 
and be lost. If the meat be plunged at first into boiling 
water for a few minutes, the surface is hardened and a 
coating formed, which keeps in the flavoring matters of 
the deeper parts. The cooking should then be continued 
slowly. Quick boiling,'except at the start, will spoil the 
best and most tender piece of meat. 

Hogs are especially apt to suffer from a parasite, which 
lives in their muscles. This parasite is a little worm 
named trichina. If the meat be eaten raw or imperfectly 
cooked, these parasites bore their way out of the alimen- 
tary canal and travel all over the body, producing the 
disease known as trichinosis. This danger may be avoid- 
ed by thorough cooking, which kills the trichinae. 

19. The Cooking of Many Vegetables is very important. 
Those which are not eaten in the green state for their 
minerals, nearly all contain starch as their chief constitu- 
ent. This starch exists in the form of tiny solid parti- 
cles which are very hard to digest. When the vegetable 
is boiled, these particles are softened and made easier to 

More digestible ? Why should they be cooked slowly ? Why should 
a joint which is to be boiled be put at first in very hot water? Why 
should the cooking be finished slowly? Why should hog-meat, 
especially, be thoroughly cooked ? 

19. What is the chief nutritive substance in vegetables ? How is it 
altered by boiling ? By roasting? 



90 COOKING. 



digest. When starch is roasted, it is converted into a 
substance known as soluble starch which readily dissolves 
in the mouth or stomach. The common belief that the 
crust of a loaf is more easily digested than the crumb, 
and toast than ordinary bread, is therefore correct. 



CHAPTER IX. 
STIMULANTS. 

1. What is Meant by a Stimulant. — In general a stimu- 
lant is something that does not nourish the body, but 
stirs it or one or more of its organs to do work. Thus 
we say that a man is stimulated to labor by the desire 
to make his family comfortable; or a lad to hard study 
by the wish to get to the head of his class; or to the use 
of his muscles to their utmost power, by the ambition to 
win a race. Some stimulus to exertion is useful: with- 
out it most of us would be slothful and ignorant and 
stupid. On the other hand, our bodies may be stimu- 
lated to attempt more than they can safely accomplish. 
Many a man breaks down from too severe labor, and 
boys and girls at school sometimes injure their health 
by overstudy, stimulated by the ambition to excel. 

2. Foods as Stimulants. — Several common articles of 
diet are named stimulants^ because their action is rather 
to excite the brain, or the heart, or the muscles, or the 
stomach to greater activity, for a time, or to decrease the 
feeling of fatigue after labor, than to nourish any organ. 
Some of these stimulants, as pepper, which makes many 

1. What is meant by a stimulant ? Illustrate. Why is some stim- 
ulus useful? How may it be an evil ? 

2. Why are several common articles of diet called stimulants ? 
What is said of their different effects ? Of those who need not even 
the least injurious ? 



92 USE OF STIMULANTS. 

foods more palatable, do little or no harm as ordinarily 
used. Others, as alcohol in all its forms, when taken at 
all are very apt not to be used in moderation, and then 
they do so much injury that they are really poisons. 
Persons in perfect health need no kind of stimulant food. 
A strong, healthy young person with rich blood, power- 
ful heart, vigorous muscles, and good digestion wants 
no pepper nor mustard nor tea nor coffee to promote his 
appetite or relieve his fatigue. He is better without 
such things; and so is a perfectly healthy man or wo- 
man. 

3. The Use of Stimulants. — Stimulant articles of diet 
are rather medicines than foods; as medicines they have 
their use. A man sometimes comes home after his day's 
work, fagged out in body and mind, without appetite, and 
feeling restless and jaded. Then a cup of tea will often 
remove the feeling of fatigue, enable him to eat and 
digest his supper, soothe his nerves, and let him get a 
good night's rest. The tea has not itself nourished him, 
but it has enabled him to take proper nourishment, and 
in that way has done good. 

We may compare the safer kinds of stimulants, as tea 
and coffee, to the ^^ blower" of a grate. When a fire is 
burning badh^ the blower is useful, but if the fire is 
burning well it only does harm. It leads to a very rapid 
using up of the coal or wood, without any correspond- 
ing benefit, and does not itself supph^ fresh fuel. 

4. The Abuse of Stimulants is chiefly due to the fact 
that the brief relief from fatigue, and the feeling pro- 

3. Rightly considered what are these stimulants ? What is said of 
their effects when properly used ? To what may they be compared ? 

4. To what is the abuse of stimulants chiefly due ? What are the 
wrong and right ways of regarding them ? 



ABUSE OF STIMULANTS. 93 

duced by them of being able to do more work, is taken 
as a sign that they have really strengthened the body. 
They come to be regarded as foods which may be taken 
safely so long as there is an appetite for them, and not 
as medicities to be taken always with caution. 

5. Tea and Coffee. — The amount of nourishment con- 
tained in a cup of tea or coffee, apart from the sugar or 
milk put into it, is trivial. Both liquids have, however, 
a great power of making the brain tranquil, and of re- 
moving the feeling of fatigue or worry. When taken in 
moderate quantity, they rarely leave injurious after- 
effects. Some persons, however, experience a sensation 
of fulness in the head after taking coffee, or are kept 
awake all night by a small cup of it ; they should of 
course avoid it. For relieving muscular fatigue, tea or 
coffee is far superior to any kind of alcoholic drink. 
Sportsmen out for a day's shooting find a flask of cold 
tea in the pocket far more useful than a flask of spirits. 
Generals who have commanded troops in campaigns 
agree that a ration of coffee is better than one of 
whiskey for tired soldiers. All commanders of arctic 
exploring expeditions have come to the conclusion that 
the men bear fatigue, cold, and anxiety better on tea or 
coffee than when supplied with rum or whiskey instead. 

6. The Harm done by Excessive Tea- or Coffee-Drinking. 
— Injurious effects of excessive tea- or coffee-drinking 
are most commonly seen in those who are young, or 
who, though older, lead indolent lives. The conse- 

5. What is the chief nourishment in a cup of tea or coffee ? 
Effect of tea or coffee on the body ? When should coffee be 
avoided ? Effect of tea or coffee on muscular fatigue ? Illustra- 
tions. 

6. What class of persons are most liable to be injured by tea- and 



94 ALCOHOLIC STIMULANTS. 

quences of excessive tea-drinkijig are, dryness of the 
mouth, loss of appetite, biliousness, a feeling of sick- 
ness at the stomach, nervousness and unreasonable 
trembling, troubled sleep and terrifying dreams. In 
their full development, these symptoms are often met 
with in professional ^^tea-tasters;" but they are not un- 
frequent in idle men and women, who take no part or 
interest in the world's work and who strive to keep 
themselves from utter stagnation by drinking strong 
tea, morning, noon, and night. 

Coffee taken in excess tends rather more than tea to 
dilate the channels through which blood passes to the 
brain. It then causes a feeling of ^^ fulness" in the 
head and flushes the face. It is more apt to produce 
wakefulness than is tea; but its action on the digestive 
organs when it is taken in excess is not so bad. Some 
people have their digestion disturbed by co^t^with milk^ 
so that it gives them hazy vision, dizziness, and head- 
ache, while the same persons experience no harm from 
the same amount of coffee without milk. 

7. Alcoholic Stimulants. — Young persons do not gener- 
ally know what alcoholic stimulants are, and often sup- 
pose them to be only the various forms of *^ strong 
spirits," such as brandy, rum, gin, and whiskey. But all 
wines contain alcohol, and so do all beers, cordials, and 
even cider, except when it is perfectly new. Many of 
the ^Uonics'' so widely advertised, are also alcoholic 
drinks, sold under a false name. We have already 

coffee-drinking? Consequences of excessive tea-drinking? In 
whom most often fully seen? Wiiat other class of people are apt to 
exhibit them ? How do the effects of excessive coffee-drinking differ 
from those produced by tea? 

7. Name some drinks containing alcohol. Why is it obvious that 



ALCOHOL AS A FOOD, 95 

learned that alcohol tends to injure seriously the con- 
nective tissues, the muscles, and the skin. We shall 
later learn that it acts quite as injuriously on many 
other parts of the body ; for example, the heart and 
the brain and the lungs. It is thus obvious that all 
drinks containing alcohol are dangerous, and the more 
so the greater the quantity of alcohol in them. For the 
present, we will confine ourselves to the question 
whether alcohol has any just claim to be called a food. 
Foods are useful to build tissues, to supply strength 
or working power, or to maintain our animal heat. 
Does alcohol do any one of these ? 

8. Is Alcohol a Tissue-Forming Food?— To this the 
answer is certainly, no ; so far at least as useful tissue 
is concerned. Its consumption often leads to excessive 
and harmful overgrowth of connective tissue and fat, 
but it does not lead to development of muscle or brain 
or gland. 

9. Is Alcohol a Strengthening Food? — To this the 
answer is also no. Alcohol in small doses is a stimulant 
to brain and muscle, and may for a short time excite 
them to overwork or to work when they should be rest- 
ing. But as it nourishes neither of them, the final result 
is bad. The brain and muscle are left in an injured 
state. As regards the brain, the consequence is often 
insanity (Chap. XVIII. ). As regards the muscles, very 
careful experiments have been made on soldiers who 



alcoholic drinks are dangerous ? In deciding the claims of alcohol 
to be a food, what properties of foods must we recall ? 

8. What is said of alcohol as a tissue-forming food ? 

9. Is alcohol a strengthening food? How may it lead to over- 
work? Results? What were the results of experiments made on 
soldiers as to the action of alcohol on the muscles ? 



9^ ACTION OF ALCOHOL ON ANIMAL HEAT. 

were given definite tasks to accomplisli. The result was 
that on the da3^s on which they were supplied with 
spirits, they could neither use their muscles as power- 
fully, nor for as long a time, as on the days when they 
got no alcoholic drink. 

10. Does Alcohol keep up the Heat of the Body? — To 
this question, also, the answer is no^ though this may 
seem strange in view of the fact that a drink is often 
taken *' to warm one up." The apparent inconsistency 
is easily explained. We have already learned that our 
feeling of being warm depends on the nerves of the 
skin (p. 76). We have no nerves which tell us whether 
heart or muscles or brain are v^armer or cooler. These 
inside parts are always hotter than the skin, and if 
blood which has been made hot in them, flows in large 
quantity to the skin, we feel warmer because the skin is 
heated. As alcoholic drinks make more blood flow 
through the skin, they often make a man feel warmer. 
But their actual effect upon the temperature of the whole 
body is to decrease it. The more blood that flows 
through the skin, the more heat is given off from the 
body to the air, and the more blood so cooled is sent 
back to the internal organs. The consequence is that 
alcohol cools the body as a whole, though it may for a 
short time heat the skin. That a large dose of alcohol 
leads to excessive loss of heat from the body, has been 
thoroughly proved by many observations on drunken 
men, and by experiments on the lower animals. 



10. Does alcohol maintain the heat of the body? Why does a 
drink sometimes make a person feel warmer? What is the real 
effect of alcoholic drinks on the temperature of the body? How has 
it been proved ? 



ALCOHOL AS A MEDICINE, 97 

11. Alcohol is a Medicine. — In many diseases the body 
needs rousing to make a special effort, and the physician 
has to order an alcoholic stimulant, or some substance 
which acts on the body in a like way. Not merely is it 
a powerful stimulant, but in moderate doses it checks 
for a time the oxidations of the body, and thus dimin- 
ishes the wasting of its organs. This only harms a 
healthy well-nourished person, but may often be use- 
ful in impaired health. In fact, alcohol is a medicine, 
and often a very valuable one. It may be classed with 
strychnine, arsenic, opium, and other drugs, which are 
useful in various impaired states of health, but so dan- 
gerous that they should only be taken on the advice of 
a doctor, and in the exact manner and quantity ordered 
by him. 

Probably few physicians would be willing to omit 
alcohol from the list of remedies; but many patients 
have acquired drinking habits from first taking an alco- 
holic stimulant on the ^' doctor's advice." Many medical 
men, for this reason, prescribe it in some disguised form; 
and this is the better plan. 

II. When may it become necessary to take alcohol internally? 
With what poisonous drugs classed ? Precautions to be used? 



CHAPTER X. 

DIGESTION. 

1. Introductory. — We learned almost at the outset of 
our anatomical study, that the alimentary canal is but 
a tube (Fig. i) which, beginning at the mouth, runs 
through the neck, chest, and abdomen', and ends by 
opening again on the outside at the lower part of the 
trunk of the body. We now have further to observe 
that it is wide in some parts, like the stomach and large 
intestine (all to be presently described), and narrow in 
others, like the gullet and small intestine, which will 
also be presently described; some parts of it are straight 
and others coiled; but it has no branches which reach 
out into the arms or legs or brain. Nevertheless, after 
a good dinner we feel no doubt that what we have eaten 
is going to strengthen our limbs and every other part of 
the body. To accomplish this, the nourishing portions 
of the food must get through the walls of the alimen- 
tary canal, and then be carried to all the organs. 

2. Digestion — The first important thing that happens 
to our food inside the alimentary canal, by way of pre- 
paring it to reach distant organs, is that its solid parts, 
or at least those of them which are nourishing, are dis- 

1. How do the various parts of the alimentary canal differ ? What 
must happen in order that food may nourish all parts of the body ? 

2. What is the first important work inside the alimentary canal to 



ABSORPTIO^r. 99 

solved. This is brought about by the action of peculiar 
liquids made inside the body, and poured into the mouth, 
stomach, or intestines. The process of getting all the 
valuable part of the things which we have eaten, into a 
liquid state, is known as digestion, 

3. Absorption. — The second step is to get this nourish- 
ing liquid into the blood. As it slowly passes along the 
alimentary tube it is gradually soaked up or absorbed by 
the walls of the latter, as if they were lined with blotting- 
paper, and either mixed at once with the blood which 
flows in them; or, first, with another liquid, the lymph, 
which is afterwards poured into the blood. The taking 
up of digested food by the lining of the alimentary 
canal, is known as absorption, 

4. The Alimentary Canal is about thirty feet in length, 
much the longest portion of it being contained in the 
abdomen. At its beginning (Fig. 24) it is tolerably wide 
and forms the mouth and throat cavities. In the neck and 
chest, it has the form of a narrow, nearly straight tube, 
the gullet or oesophagus. The lower end of the gullet 
passes through the diaphragm and then almost immedi- 
ately opens into the much wider stoinach (Fig. 32). The 
stomach is followed by the narrow greatly coiled stnall 
intestine; and this in turn opens into the large intestine, 
which is the last portion of the alimentary canal. 

prepare food for nourishing the body ? How brought about ? What 
is the process called ? 

3. What is the second step indigestion? How does the nourishing 
liquid get into the blood ? What is lymph ? What is this process of 
taking up digested food called ? 

4. How long is the alimentary canal ? What easily contains the 
longest portion of it ? What is the gullet ? Where does it end ? 
What follows the stomach ? What is the large intestine ? 



100 



MUCOUS MEMBRANE. 



5. The Lining of the Alimentary Canal is a soft, red, 

moist kind of skin, named 
a mucous tnefnbrane. You can 
easily see part of it on ex- 
amining the inside of your 
mouth with the help of a 
looking-glass. This mucous 
membrane has two func- 
tions, secretion and absorption. 
Imbedded in it are thou- 
sands of tiny glands (p. 64), 
which, instead of making 
perspiration or oily matter, 
like the skin-glands, pour 
out very different liquids, 
which aid in swallowing and 
digesting. 

6. The Mouth-Chamber 
(Fig. 24) opens in front be- 
tween the lips, and behind 
Fig. 24. — The mouth, nose, and into the throat-chamber or 

pharynx, with the commencement of 

the gullet and larynx as exposed by pharynx. It is bouudcd On 

a section, a httlc to the left of the mid- ^ -^ 

f ^J^fiwf ^/^w;nH''Ain!''^^'^l^^^^^ the sides by the cheeks, be- 

/?, gullet; c, windpipe; ^, epiglottis j J ' 

/, soft palate; g, opening of Eusta- i u^ ^i^ \rsx\<y\\e ;^hove hv 

chian tube; k, tongue; /, hard palate; ^^^^ ^Jy tne tongue, auOVC Uy 

?«, the sphenoid bone on the base of .-i ^ j.^7^4„ T'U^ -f*-^*,*- ^r^-4-:^,, 

the skull; «, the fore part of the skull- Ui^ palate. 1 he front portion 

cavity; ^, /, ^, the turbinate bones of - ^, 1^7 ^ .i_ 

the outer side of the left nostril-cham- OI the palate, /, Separates the 

mouth from the nose, and 
is supported by bone. This portion is named the hard 
palate. The posterior portion of the palate, /, is soft 

5. What is the lining of the alimentary canal ? Where can you 
easily see it ? What are its functions ? How does it aid in swallow- 
ing and digesting ? 

6. Describe the mouth-chamber. The hard palate. The soft pal- 




THE TEETH. 10 1 

and contains no bone. It forms a curtain between the 
mouth and pharynx; there hangs down from its lower 
border a soft fleshy projection, named the uvula^ gener- 
ally miscalled the palate. If the mouth be held wide 
open in front of a mirror, the uvula can be easily seen, 
and also the opening, between the soft palate and the 
root of the tongue, which leads into the pharynx. This 
opening is named the isthmus of the fauces. On its sides 
are the tonsils. 

7. The Teeth stand almost alone among the organs 
of the body, in the fact that when broken or seriously 
injured or much worn, they are not repaired. To 
do their duty they must be very hard, and they gain 
this hardness by being so largely made of mineral 
matter that their living animal part is not present in 
sufficient quantity to rebuild them when they are broken 
or decayed. During life two sets of teeth grow. The 
first, named the milk-teeth^ are developed and shed dur- 
ing childhood. The second set, named the per7iianent 
teethy follow the milk-teeth. If they are lost, we must 
go to the dentist, for no others will grow to take their 
places. 

8. The Forms and Uses of Diflferent Teeth. — Every tooth 
consists of a crown^ the part which projects into the 
mouth; of a narrower neck^ surrounded by the gums; 
and of one or more roots or fa?igs, tightly fitted into pits 
(called sockets) in the edges of the upper and lower jaw- 
ate. What is the opening seen between the soft palate and root of 
the tongue ? The organs on each side ? 

7. How do the teeth differ from most other organs as to repair ? 
How is this accounted for ? What is said of the first set of teeth ? 
The second? 

8. Of what parts does a tooth consist ? Give names of the different 
teeth. Describe the incisors. Canines. Molars. Bicuspids. 



102 



THE TEETH. 



bones. On account of differences in the shape of their 
crowns, and in their uses, the teeth are divided into in- 
cisors^ canines^ bicuspids^ and molars. The incisors (Fig. 25) 
have sharp chisel-shaped edges and are adapted for cut- 
ting our food. The canines (Fig. 26) or eye-teeth are 






Fig. 26. 



Fig. 27. 



Fig. 28. 



Fig. 25. 

Fig. 25. — An incisor tooth. 
Fig. 26. — A canine or eye tooth. 

Fig. 27.— a bicuspid tooth seen from its outer side ; the inner cusp is accord- 
ingly not visible. 

Fig. 28.— a molar tooth. 

pointed and serve the same purpose: they are very long 
and sharp in dogs and cats, and are useful to these ani- 
mals in holding their prey. The molars (Fig. 28) have 
broad rough ends to their crowns and are suited to grind 
and crush. The bicuspids (Fig. 27) are like the molars 
but not so large. 

9. Arrangement of the Teeth in the Jaws. — In the 
milk-set, there are twenty teeth, ten in each jaw. Begin- 
ning in the middle line and going back, we find in order, 
on each side, two incisors, one canine, two molars. 

The permanent teeth number sixteen in each jaw. 
Beginning at the middle line, we find successively two 
incisors, one canine, two bicuspids, and three molars, in 
each half of each jaw. The incisors and canines take 
the places of the milk-teeth of the same names. The 

9. Arrangement of milk-teeth. Of permanent teeth. Which ones 
are added as the jaw grows larger ? What of the wisdom-teeth ? 



PERMANENT TEETH, 



103 



bicuspids supplant the milk-molars. The permanent 
molars are added as the jaw grows larger; the hindmost 




Fig. 29. — Section through a tooth still imbedded in its socket, i, enamel; 2, den-, 
tine; 3, cement; 4, the gum; 5, the bone of the lower jaw; r, the pulp-cavity. 

ones, often named the wisdom-teeth^ do not appear until 
about the twentieth jear of life. 



I04 STRUCTURE OF A TOOTH, 

10. The Pulp of a Tooth.— If a tooth be broken open, a 
cavity (<;, Fig. 29) will be found inside it. It is named 
the pidp-cavityy and during life is filled with a soft red 
very sensitive core, full of blood and nerves, named the 
ptclp. At the tip of the fang, or of each fang, if the tooth 
has more than one, is a small aperture through which 
the nerves and blood enter. The pulp nourishes the 
tooth; on account of the nerves in it, it gives rise to 
great pain when exposed or inflamed. When a dentist 
speaks of destroying or removing the ** nerve" of a tooth,' 
he means the pulp. 

11. The Hard Parts of a Tooth (Fig. 29) are made of 
three different materials. Surrounding the pulp-cavity 
is dentine or ivory: an elephant's tusk is made of dentine. 
Covering the ivory in the crown, is enamel, the tissue of 
the body which contains least animal matter. It is so 
hard that it will strike a spark with steel. Covering the 
dentine in the fang, is what has been named the cefnentj 
it is but a thin layer of bone under another name. The 
dentine is harder than bone, though not so hard as 
enamel. 

12. Hygiene of the Teeth. — A great portion of the hard 
parts of a tooth consists of a very hard kind of chalk, 
and like chalk it is readily eaten away, or dissolved, by 
sour or add liquids. The mouth should therefore be 
well washed after eating lemons or other sour things:^ 
and acid medicines should be sucked through a glass 

10. What is the pulp of the tooth ? How do blood and nerves get 
into the pulp ? Use of the pulp. Why called the nerve ? 

11. What is dentine? Enamel? Cement? How does dentine 
compare with enamel ? 

12. What is the effect of acids on the teeth ? What precautions are 
therefore necessary for their preservation? How may acids be made 
in the mouth ? What is said of decay of the teeth ? 



THE TONGUE. 10$ 

tube, and swallowed after as little contact with the teeth 
as may be possible. 

Many foods if kept in the warm moist mouth, decom- 
pose and give rise to acids: the teeth should therefore 
be thoroughly cleansed twice daily, with a soft tooth- 
brush and tepid water. Finely powdered chalk or a 
little soap may be placed on the brush with advantage, 
as they counteract any acids which may be present. The 
enamel is not so easily attacked as the deeper parts of a 
tooth; but once the enamel is injured, the dentine is apt 
to decay rapidly. Small cavities in the enamel are not 
easily discovered unless they are on the outer side of the 
tooth. Remnants of food collect in them and, making 
acids, rapidly eat away the tooth. The teeth should 
therefore be thoroughly examined by a dentist two or 
three times a year, and all cavities filled. 

13. The Tongue (Fig. 60) is endowed not only with a 
delicate sense of touch, but is the chief organ of the 
sense of taste. Being highly muscular and very mov- 
able, it also plays a great part in guiding food inside the 
mouth, so as to push it between the teeth until it is 
properly chewed, and then to drive it on into the 
pharynx to be swallowed. As an organ of taste, we shall 
study the tongue later (Chap. XIX.). 

14, What a " Furred Tongue" Indicates. — In health the 
mucous membrane covering the tongue is moist, covered 
by little ^* fur** and, in childhood, of a bright red color. 
In adults, the natural color of the tongue is less red, ex- 
cept around the edges and at the tip. When any part of 

13. Of what is the tongue the chief organ? What muscular work 
does it perform ? 

14. What is said of the covering of the tongue ? Color? Indica- 
tions of disordered digestion ? 



I06 SALIVARY GLANDS. 

the alimentary canal farther on is out of order, the 
tongue is apt to be covered with a thick yellowish coat- 
ing, and there is a ^'bad taste" in the mouth. This may 
in most cases be taken as a sign that there is something 
wrong with the stomach. 

15. The Salivary Glands. — The liquid which moistens 
the mouth is named saliva. It consists of a slimy fluid, 
named muctis^ made, or secreted^ as we say in physiology, 
by the tiny glands of the mucous membrane, mixed 
with a more watery secretion made by three pairs of 
salivary glands. These glands lie outside the mouth, but 
pour their secretion into it through tubes or ducts. Two 
of the salivary glands are placed in front of the ears ; 
their ducts open on the inside of the cheek opposite 
the second upper molar tooth. In the disease known 
as inumps they become greatly swollen. The other sali- 
vary glands lie between the halves of the lower jaw- 
bone. Their ducts open into the mouth beneath the 
tongue. 

16. The Uses of Saliva are several, (i) It keeps the 
mouth moist and enables us to speak with comfort. 
This is well illustrated by the trouble from dryness of 
the mouth experienced by many young orators when 
they first try to speak in public. The dryness is due 
to the fact that nervous excitement for a time para- 
lyzes the salivary glands and stops their secretion. (2) 
The saliva enables us to swallow dry food. A cracker 
when chewed would give rise merely to a heap of dust, 

15. What is saliva? How made? Describe the position of the 
salivary glands. Where do the ducts ©f each pair open ? 

16. What is the first use of saliva? Illustrate. The second? 
Illustrate. The third ? Illustrate. The fourth ? 



USES OF SALIVA. I07 

impossible to swallow, if it were not moistened. This 
fact was made use of in the former East Indian rice- 
ordeal. All suspected persons were brought together 
and given parched rice to eat. The guilty individual, 
believing that his gods would bring his crime to light, 
usually had his salivary glands paralyzed by fear, and 
so could not secrete enough saliva to enable him to 
swallow the dry rice ; while those with clear con- 
sciences had no difficulty. (3) Saliva, by dissolving 
many solid substances, enables us to taste them. 
Things in the solid state cannot be tasted, as you may 
easily discover by wiping your tongue dry and placing 
a piece of lump-sugar on it. Until a little moisture has 
come out and dissolved some of the sugar, no taste will 
be perceived. (4) Saliva turns starch, which is not itself 
nourishing, into sugar, which is. 

17. Digestion in the Mouth, — By means of the teeth, the 
solid parts of our food are cut and crushed. At the 
same time, they are softened and made ready for swal- 
lowing by mixture with the saliva. Saliva also alters 
some nourishing substances in the food, and so changes 
them that instead of being insoluble they become readily 
soluble. 

18. The Action of Saliva upon Starch. — Raw starch 
may be 'mixed with water, but will not dissolve in it. 
After a while, all the starch settles down from such a 
mixture. When starch is boiled in water, it swells up 
very much and mixes more thoroughly with the water 
than raw starch does, but still it does not dissolve. If 

17. How is digestion carried on in the mouth? What are the uses 
of saliva ? 

18. What happens when starch is mixed with water? When 
boiled? What happens if you strain a solution of sugar and water? 



1 08 MA S TIC A TION, 

you dissolve some salt or sugar in water, and pour the 
solution into a bag made of three or four thicknesses 
of very fine muslin, the salt or sugar will come through 
just as freely as the water. But if you try the same 
experiment with boiled starch, you will find that the 
water comes through, but leaves most of the starch 
behind it inside the bag. The tiny openings or pores 
of the mucous membrane lining the alimentary canal, 
through which the dissolved food has to pass when it is 
absorbed into the blood, are far smaller than the holes in 
the finest muslin ; and starch, whether raw or boiled, could 
not get through them. The saliva turns starch into sugar, 
which dissolves rapidly and is very easily absorbed by 
the mucous membrane. In this way bread and corn 
and arrowroot and many other articles of diet which 
contain much starch (p. 87) are enabled to nourish our 
bodies. 

19. Why Food should be well Masticated. — Some per- 
sons eat as if all that their teeth and mouth had to do 
was to bite and swallow : they seem to believe that their 
stomachs are like the gizzard of a bird, constructed to 
crush and grind. Nature having provided man with 
teeth, has given him no gizzard : the human stomach 
will certainly get out of order if it is frequently called 
upon to do the work of one. Our molar teeth are so 



Of starch ? How may the pores of the mucous membrane of the 
alimentary canal be compared to muslin ? How does the action of 
saliva enable starch to get through these pores ? Why could we not 
digest bread, corn, arrowroot, and like food without saliva ? 

19. What duty besides biting and swallowing have the teeth in 
connection with digestion ? Where do fowls crush hard food ? What 
is the consequence if we eat as if we had gizzards ? What is the evi- 
dent duty of our molars ? How does chewing affect the salivary 
glands ? 



USE OF MASTICATION, lOQ 

clearly fitted to break up our food into small pieces that 
there can be no doubt as to what their use is. 

The chewing or 7nasticatio7i of food also causes a 
greater flow of saliva. When we are not eating, the 
salivary glands secrete little; but as soon as we com- 
mence to chew, they begin to be more active. If food 
be swallowed hastily, it is not mixed with sufficient 
saliva, and in consequence, its starchy parts are imper- 
fectly digested. 



CHAPTER XI. 
DIGESTION, CONCLUDED. 

1. The Pharynx (Fig. 30) is a muscular bag lined by 
mucous membrane; it opens at its lower end into the 
gullet, b. Not only our food, but also the air which we 
breathe, has to pass through the pharynx, for into its 
upper portion, above the level of the palate, /, /, the 
inner ends of the nostril-chambers open. Under the 
soft palate,/, is the aperture through which food is sent 
from the mouth; and, lower still, another opening, be- 
hind the root of the tongue, through which air enters 
the passage, Cy which transmits it to the lungs. 

2. Swallowing or Deglutition is the process of sending 
food or drink from the mouth to the stomach. The 
liquid, or the mass of chewed solid food, is collected on 
the upper surface of the tongue, and then pushed into 
the pharynx. As soon as it has left the mouth, the 
opening between mouth and pharynx is closed, to pre- 
vent its return. At the same instant the soft palate 
is raised, so as to separate the upper from the lower 
portion of the pharynx: in this way the food is pre- 
vented from getting into the nose. The lid, ^, named 

1. What is the pharynx? What besides food passes through it? 
What opens into it above the palate ? Below ? Behind the root of 
the tongue? 

2. What is deglutition ? How is food sent from the mouth to the 
pharynx? How is its return prevented? How is it kept from getting 



SWALLOWING. 



Ill 



the epiglottis^ which overhangs the aperture leading to 
the windpipe, r, is also shut 
down. Therefore, when the 
muscles of the pharynx con- 
tract and press on the food, 
the only way it can go is 
into the gullet, b. Occasion- 
ally a morsel '' goes the 
wrong way," and gets into 
the air-passage, causing a fit 
of coughing which drives it 
back into the pharynx. The 
things which we swallow are 
hurried through the pha- 
rynx very fast, so as to get 
it clear, and enable us to 
breathe again. 

3. The Passage of Food and 
Drink along the Gullet or oeso- 
phagus, is slow. A mouthful 

of food or drink when it has ryni?-4i;r?he%TZ'encemenfVth; 
r^^ir^^r^A 4- u ^ .^ u J guUet and laryDX, as exposccl by a scc- 

entered the oesophagus does fion, a little to the left of the middle 

^ J J . . . of the head, a, vertebral column; b, 

not drop down that tube into gullet; c, windpipe; d, larynx; e, epi- 

1 1 . , glottis: y; soft palate;^, opening of 

the stomach, like a brick Eustachian tube; the letters ^,/,^ are 

placed in the pharynx; k, tongue; /, 

lallins^ down a chimney, but hard palate; w, the sphenoid bone on 

-^ the base of the skull; «, the fore part 

is seized by the muscular of the cranial cavity; o, p ^' the 

•^ turbinate bones of the outer side of the 

rings in the coat of the gul- ^^^^ nostril-chamber. 

let, which contract one after another and push it along. 




into the nose ? Into the windpipe ? What does it enter when forced 
out of the pharynx? What is meant when a morsel of food is said to 
have gone the wrong way ? Why is food sent quickly through the 
pharynx? 

3. How do food and drink pass along the gullet ? Illustrate. 



112 THE STOMACH. 

For this reason, horses and many other animals are able 
to swallow, although they usually eat with their mouths 
much lower than their stomachs; and jugglers are able 
to drink a glass of water while standing on the head. 

4. The Stomach (Fig. 31) is a dilated portion of the 
alimentary canal, which lies at the lower end of the oeso- 
phagus, in the upper part of the abdomen, rather more 
on the left than the right side of the body (see Fig. 2). 
Outside its lining mucous membrane, is a thick muscular 
coat. 



Fig. 31.— The stomach viewed from the front, d, lower end of the gullet; a^ 
position of the cardiac aperture; 3, the fundus; c, the pylorus; ^, the first part of 
the small intestine. 

The gullet, ^, opens into the upper side of the stomach 
by an aperture named the cardiac orifice. The left end of 
the stomach gradually narrows to the commencement of 
the small intestine, e. The place, ^, where stomach and 
intestine meet is named the pylorus^ and the opening 
which places their cavities in communication is the pyloric 
orifice. When moderately distended, the stomach con- 
tains about three pints. 

4. Position of the stomach ? What is outside its mucous mem- 
brane ? How and where does the gullet enter it? How does the 
stomach join the small intestines ? What is the pylorus ? The py- 
loric orifice ? Capacity of the stomach ? 



DIGESTION IN THE STOMACH, II3 

5. The Gastric Juice. — The mucous membrane of the 
stomach is almost entirely made up of thousands of tiny- 
glands, placed side by side nearly as close as they can 
be packed. The liquid which these glands make is 
poured into the stomach, and is known as the gastric 
iuice. If you imagine a piece of honeycomb reduced very 
much in size, and that its cells answer to the glands, you 
will have a fair idea of how the glands lie in the mucous 
membrane of the stomach. To complete the resem- 
blance, each cell would have to be open at one end, and 
through this opening to pour its honey on the surface of 
the comb, and to keep on making honey to take the 
place of that it had emptied out. The liquid, too, would 
have to be much thinner than honey, and sour or acid^ 
instead of sweet. 

6. Digestion in the Stomach. — When the healthy 
stomach is empty, its mucous membrane is something 
like grayish-pink velvet and its glands make hardly any 
gastric juice. As soon as food is swallowed, a great 
deal of blood flows to the mucous membrane, and it be- 
comes red. At the same time, its glands secrete abun- 
dantly, and, all over the surface, gastric juice trickles 
out, like sweat on the skin of a person perspiring pro- 
fusely. These facts were first observed many years ago, 
on a Canadian hunter, named Alexis St. Martin, who, as 
a result of a gunshot wound, had a small opening from 
the surface of his abdomen into his stomach. Through 
this opening, what was going on inside his stomach could 

5. Of what is the mucous membrane of the stomach chiefly made 
up ? What is the gastric juice ? Illustrate. 

6. What is the state of the stomach when empty ? After swallow- 
ing food ? How were these facts first observed ? What are the 
chief foods acted on in the stomach ? How are they changed ? 



114 THE MUSCLES OF THE STOMACH. 

be watched. Since then the carefui observations made 
by his physician have been confirmed by the study of 
several similar cases. 

The chief kinds of foods acted on in the stomach, are 
of albuminous nature (p. ), lean meat, white of egg, 

cheese, the gluten of bread, and so forth. They are 
turned into a condition in which they can be dissolved 
and absorbed. 

7. The Muscular Coat of the Stomach (Fig. 19) per- 
forms two duties: first, it thoroughly mixes our food 
with the gastric juice; and next, it drives it on into the 
intestine. The p3doric orifice (^, Fig. 31) is narrow, 
and surrounding it is a thick ring of muscle which 
keeps the passage closed, for an hour or more after eat- 
ing. During this time, the muscles of the stomach con- 
tracting, now in one direction and now in another, keep 
its contents in constant motion and bring every part of 
the food into contact with the gastric juice. 

When the digestive process has gone on until some 
food is ready to enter the intestine, the muscle around 
the pylorus relaxes a little from time to time; thus 
some liquified food is passed through the opening. 
When all the things which can be dissolved in the 
stomach have been passed on, the pyloric orifice opens 
wider and lets solid indigestible things get through. 
In this way buttons, coins, cherry-stones, and other such 
things which may have been swallowed reach the 

7. What are the duties of the muscular coat of the stomach ? 
What surrounds the pyloric orifice ? Its use ? What happens while 
the passage is closed ? What occurs when some food has been pre- 
pared to enter the intestine ? What occurs when the stomach has 
done all it can towards digesting its contents ? How soon after an 
ordinary meal is the stomach empty ? 



THE PYLORUS. 



115 



bowels, to travel through them and, in fortunate cases, 
be sent out of the body, along with indigestible portions 
of the food. In health the stomach is completely emp- 




FiG. 32. — The abdominal portions of the alimentary canal. ^, stomach; C, lower 
end of gullet ; P, pylorus ; Z>, y, /, portions of the small intestine, named re- 
spectively duodenum, jejunum, and ileum ; CC^ AC, TC^ DC, S-F, 7?, portions of 
the large intestine, named respectively the caecum, ascending colon, transverse 
colon, descending colon, sigmoid flexure, and rectum. 

tied in from two and a half to three and a half hours 
after an ordinary meal. 

8. The Small Intestine {D, /, /, Fig. 32), commenc- 



8. Commencement, course, and ending of small intestine ? Length 



Il6 THE LIVER, 

ing at the pylorus, ends after many windings, by join- 
ing the large. In an adult it is about twenty feet long 
and an inch and a half wide. Imbedded in its mucous 
membrane, are myriads of tiny glands, much like those of 
the stomach in shape and arrangement, but preparing 
a digestive liquid very different from the gastric juice. 
This liquid is mixed with the food, as it is slowly 
driven along by the muscles in the coat of the intestine. 
In addition, two large glands (p. 64), the liver and the 
i>ancreas^ pour their secretion into the small intestine 
near its upper end. 

9. The Liver is by fa?r the largest gland in the body. 
It is placed in the upper part of the abdomen on the 
right side (Fig. 2, le^ /^'), close under the diaphragm. 
The secretion of the liver is named bile or gall. When 
no food is being digested in the intestine, the bile col- 
lects in a pear-shaped bag, the gall-bladder^ which lies 
under the liver. As soon as food is sent on from the 
stomach, the gall-bladder empties bile upon it through a 
tube or duct which opens into the intestine about op- 
posite Z>, Fig. 32. 

Fresh human bile is a yellow-brown liquid. It is much 
like weak lye in some of its properties; and ox-bile or 
ox-gall is occasionally used by housekeepers instead of 
lye, for cleansing purposes, to dissolve and remove 
grease-spots. One chief use of bile is to aid in digest- 
ing the oily and fatty parts of our food. 

and width ? The glands of its mucous membrane ? Their secre- 
tion ? What other glands pour secretion into the small intestine ? 
Where ? 

9. What is said of the liver ? Its position ? Name of its secre- 
tion ? Where stored when not needed ? How disposed of when 
food enters the intestine? Color of bile? Why sometimes used in 
housekeeping? Use of bile in digestion? 



THE SMALL LNTESTLNE, 11/ 

10. The Pancreas lies along the lower side of the stom- 
ach. Its duct opens into the small intestine at the same 
place as the bile-duct. The secretion of the pancreas is 
vid.\Xi^A pancreatic juice. It is much like saliva in appear- 
ance, being transparent and colorless. The pancreatic 
juice is one of the most important digestive liquids. It 
acts upon starch as saliva does, turning it into sugar; it 
dissolves albuminous matters, thus completing the action 
of the gastric juice; and, more powerfully than bile, it 
promotes the absorption of fatty food. 

11. Digestion in the Small Intestine. — The soft half- 
digested food-mass which enters the intestine from the 
stomach, is named chyme. It is at once mixed with bile 
and pancreatic juice, and then, as it slowly passes along, 
has the secretion of the innumerable little glands of the 
mucous membrane of the small intestine added to it. 

The result of the combined action of these liquids is 
that any starch which escaped digestion in the mouth, is 
turned into sugar; any albuminous substances which 
had not been fully dissolved in the stomach are finally 
digested; fats, which are not acted upon at all by either 
saliva or gastric juice, are prepared for absorption. 
Digestion in the small intestine is on the whole more 
important than that which takes place in the mouth or 
stomach. The product of intestinal digestion is a highly 
nutritious creamy liquid containing all the nourishing 
matters of the food. This liquid is named chyle. It is 

10. Position of the pancreas ? Opening of its duct ? Name of its 
secretion ? Appearance ? Value ? Action on various foodstuffs ? 

11. What is chyme ? What is at once mixed with it in the intes- 
tine? What afterwards ? How do these liquids act on starch ? On 
albumens? On fats? Where does the most important part of diges- 
tion occur ? What is said of the liquid produced by digestion in the 
small intestine ? Its name ? For what is it ready ? 



ii8 



ABSORPTION 



ready to be taken up into the blood and carried to every 
organ. 

12. Absorption from the Small Intestine. — As the chyle 
passes along, it is gradually absorbed by the mucous 
membrane, which is specially adapted to fulfil this duty. 
Instead of being nearly smooth like the mucous mem- 
brane lining the mouth, it is raised up into numerous 
folds (Fig. -^Z) which greatly increase the extent of its 
surface; and thus it is enabled to absorb more and 
quicker than if it was stretched smooth and flat. The 




Pig. 33. — A portion of ihe small intestine opened to show the folds of its mucous 
membrane. 

pockets or hollows between the folds also have their 
use. The chyle collects in them and is thus prevented 
from passing along faster tlian it can be absorbed. 

13. The Villi of the Small Intestine.— All over the mucous 
membrane of the small intestine, both on its folds and 
between them, are tiny elevations, which stand up like 
the pile on velvet. Each elevation is a villus^ and, small 
though it is, contains two sets of tubes or vessels. One 

12*. For what is the mucous membrane of the small intestine 
specially adapted ? How is the extent of the surface of its mucous 
membrane increased? Use of these folds ? Of the hollows between 
them? 

13. Describe the surface of the mucous membrane of the small in- 
testine. What is a villus ? What does each villus contain ? Use of 
the villi ? Where does the chyle absorbed by them go ? 




PLATE III -A GENERAL VIEW OE THE LYMPHATICS OR ABSORBENTS. 
THAT PORTION OF THEM KNOWN AS THE LACTEALS IS SEEN AT d. PASSING 
FROM THE SMALL INTESTINE e TO THE THORACIC DUCT /. 



EXPLANATION OF PLATE III. 

A General Yiew of the Lymphatic or Absorbent System 

OF Vessels. 

e, A portion of the small intestine from which thelacteals or chyle- 
conveying vessels, d, proceed, their origin within the villi may be 
seen magnified in fig. 34; /, the duct called thoracic, into which the 
lacteals open. This duct passes up the back of the chest, and opens 
into the great veins at g, on the left side of the neck: here the chyle 
mingles with the venous blood. In the right upper, and lower limbs 
the superficial lymphatic vessels 1 1 II, which He beneath the skin, 
are represented. In the left upper and lower limbs the deep lym- 
phatic vessels which accompany the deep blood-vessels are shown. 
The lymphatic vessels of the lower limbs join the thoracic duct at the 
spot where the lacteals open into it: those from the left upper limb 
and from the left side of the head and neck open into that duct at 
the root of the neck. The lymphatics from the right upper limb and 
from the right side of the head and neck join the great veins at n. 
m m, enlargements called lymphatic glands, situated in the course of 
the lymphatic vessels. These vessels convey a fluid called lymph, 
which mingles with the blood in the great veins. 



THE LACTEALS. 



119 




set {d, Fig. 34) carry blood; the other, b, a watery liquid 
named lymph. The villi act like little roots or suckers, 
and the chyle which they absorb, 
goes, some of it into the blood 
at once, and some into the lymph- 
vessels. 

14. The Lacteals. — Lymph-ves- 
sels, like blood-vessels, are found 
in nearly every part of the body. 
Another name by which they are 
known is the absorbents. Most 
lymph-vessels contain only a thin 
colorless liquid, the lymph. But 
when chyle is being absorbed, 
the lymph-vessels of the small 
intestine take up so much of it 
that their contenJ:s become white 
and milky-looking. Hence they 
have been named the lacteals, 
from a Latin word {lac) meaning milk. The lacteals 
finally pour the chyle which they have taken up, into a 
tube, named the thoracic duct, w^hich runs up to the bot- 
tom of the neck and there opens into a large blood- 
vessel. 

15. The Large Intestine (CC, AC, TC, DC, SF, R, Fig. 
32') is two or three times as wide as the small, but only 
about five feet long. In it the absorption of the nourish- 
ing part of the food is completed, and towards its lower 

14. Where are lymph-vessels found ? Another name for them ? 
What do most contain? What do those of the intestine become filled 
with during digestion ? What name has been given them ? What do 
they do with the chyle ? Where does the thoracic duct pour its con- 
tents into the blood ? 

15. Size of the large intestine ? Uses? 



Fig. 34. — Two villi from the 
inside of the small intestine, mag-- 
nified eighty times; d, d, blood- 
vessels; 3 and c, lymphatic vessels 
or lacteals. 



I20 SUMMARY CONCERNING DIGESTION, 

end, in the rectum, the indigestible residue collects, 
ready to be expelled from the body. 

16. Summary. — When digestion and absorption are 
completed, all the useful portions of a meal have at last 
been mixed with the blood. Some of them, as water, 
were ready for absorption without undergoing any 
change; all we had to do was to swallow them, and the 
coats of the stomach took them up at once, if there was 
not too much of them. Others, as a pinch of salt or a 
lump of sugar, were ready to dissolve at once. Still 
others, like the lean of meat, and starchy foods, had to 
be changed by the digestive liquids before they could 
be dissolved. 

Some were changed by saliva, some by the gastric 
juice, others by the liquids of the intestines; but sooner 
or later, in mouth or stomach or bowels, they were made 
ready for absorption. 

Some of the nutritive liquid was absorbed by the 
blood-vessels of the stomach; more by the blood-vessels 
of the intestinal villi; still more by the lacteals. What 
little may still have been left, was sucked up into the 
blood- and lymph-vessels of the large intestine. But no 
matter where it was absorbed, or by what vessels, it 
finally reaches the blood, and supplies it with water and 
minerals and albumens and fats and sugar, to be carried 
to every organ. 

i6. What has happened when the digestion and absorption of a 
meal are completed? Name a food-stuff absorbed without change. 
One which has to be simply dissolved. Some which had to be changed 
by the digestive juices before they could be absorbed. Name the 
liquids used in changing them. Name the vessels concerned in the 
absorption. With what does the absorbed liquid supply the blood ? 



PRACTICAL HINTS FOR TEACHERS. 121 



APPENDIX TO CHAPTER XI. 

The main points in the anatomy of the alimentary canal may be 
easily studied on a kitten, puppy, or rat. Superfluous kittens and 
puppies have so often to be drowned, that no unnecessary taking of 
life is called for. The animal may be more mercifully killed by shut- 
ting it up in a small tight box along with a small sponge soaked in 
chloroform, for ten minutes. A tin cracker-box does very well. 

Cut away, with strong scissors, the front of the chest and abdomen of 
the dead animal, taking care not to injure the contents of those cavi- 
ties. Dissect off the skin on the front and sides of the neck. Re- 
move the larynx, trachea, lungs, and heart. 

The gullet, a slender muscular tube, will now be exposed in the 
neck; trace it through the chest; note the relative positions of the 
abdominal viscera as now exposed, before displacing any of them; 
then turning the liver up out of the way, follow the gullet in the ab- 
domen until it ends in the stomach. 

Note the form of the latter organ ; its projection (fundus) to the 
left of the entry of the gullet; \is girat and small curvatures; its x\2X- 
row er pyloric portion on the right, from which the small intestine pro- 
ceeds. Attached to the stomach, and hanging down over the other 
abdominal viscera, notice a thin membrane, the ovientuvi. 

Follow and unravel the coils of the small intestine, spreading out as 
far as possible the delicate membrane {inesentery>) which slings it. In 
the mesentery are numerous bands of fat, running in which will be 
seen blood-vessels and lacteals. 

The termination of the small intestine by opening into the large. 
Observe the ccectan or blind end of the latter, projecting on one side 
of the point of entry of the small intestine; on the other side follow 
the large intestine until it ends at the anal aperture, cutting away 
the front of the pelvis to follow its terminal portion {rectum). The 
portion between the caecum and the rectum is the colo7i. 

Spread out the portion of the mesentery lying in the concavity of 
the first coil {duodenum) of the small intestine; in it will be seen a 
glandular mass, the pancreas. 

Observe the portal vein entering the under side of the liver by sev- 
eral branches. Alongside it will be seen the gall-duct, formed by 
the union of two main branches, and proceeding, as a slender tube, to 
open into the duodenum a short way from the pyloric orifice of the 
stomach. In a kitten or puppy the gall-bladder will be seen on the 
under side of the right half of the liver. 

Note the spleen: an elongated red body lying in the mesentery, 
behind and to the left of the stomach. 

Divide the gullet at the top of the neck, and the rectum close to the 
anus, and, severing mesenteric bands, etc., by which intermediate 
portions of the alimentary canal are fixed, remove the whole tube; 
then cutting away the mesentery, spread it out at full length, and 



122 PRACTICAL HINTS FOR TEACHERS, 

note the relative length and diameter of its various parts; and that 
the small intestine forms by far its longest portion. 

Open the stomach; note, in the rat, that \.\\^inucous membrane lining 
the fundus is thin and smooth, and is sharply marked off from the 
thick corrugated mucous membrane lining the rest of the organ. This 
is not the case in the stomach of dog, cat, or man. Pass probes 
\.\\xo\i%\\ xki^ cardiac orifice \x\\.o the gullet and through the py /arte ori- 
fice into the duodenum. 



CHAPTER XII. 
HYGIENE OF THE DIGESTIVE ORGANS. 

1. Why Care of our Digestion is an Important Duty. — 

When the digestive organs are all in good working 
condition, appetite is healthy, our meals are enjoyed, the 
temper is cheerful, the body vigorous and well nour- 
ished, and life pleasant. If the stomach, liver, or intes- 
tines fail in their duty, the picture is reversed. Appetite 
is wanting, the brain and muscles are ill nourished, every- 
thing is regarded from a gloomy point of view, work of 
any kind is a burden, and life a weariness. It is plain 
from this, that in most cases, the man with a good di- 
gestion and, in consequence, a well-nourished body and 
cheerful active mind, has much better chances for suc- 
cess in life than one whose energies are weighed down 
by bad digestion, and consequent ill heath. 

Not merely from its bearing on our own personal 
happiness and welfare, but as a matter of duty towards 
others, it is of primary importance to preserve the 
digestive organs in a healthy natural state. A man 
with good digestion is pretty sure to be an agreeable 
and encouraging friend or companion; while the chances 
are that one who digests badly, will be irritable, de- 
pressed, and disagreeable. 

I. How does a good digestion influence our health and happiness? 
A bad ? Our chances for success in life? Why is it a duty towards 
others to try and maintain our digestive organs in good condition ? 



124 DYSPEPSIA, 

2. Dyspepsia is the name commonly used to indicate 
difficult or painful digestion. It may take many forms 
and be due to imperfect action of different organs. In 
certain cases, it is, no doubt, unavoidable; some unfortu- 
nate people have weak stomachs, or sluggish livers, as 
others have feeble muscles or poor eyes, from causes 
beyond their control. But in the great majority of cases, 
dyspepsia is due to some imprudence in conduct. Its 
most frequent cause is unwise eating and drinking; but 
mental overwork, neglect of muscular exercise, lack of 
fresh air, late hours, and improper clothing, all play 
their part in various cases. Probably not more than 
one person out of five of those who live in towns or 
cities, reaches the age of forty, without suffering from 
some form of dyspepsia, which might have been avoided 
by wiser habits during early life. Once it has made its 
appearance, dyspepsia is extremely difficult to get rid 
of. How best to avoid it, is therefore a very important 
branch of hygiene. 

3. The Intervals between beginning Meals should be 
not less than four hours, five is better; except in the case 
of young children and invalids, who require food more 
often, and in small quantities at a time. As we have 
learned (p. 115), the stomach is only emptied about two 
and a half or three hours after an ordinary meal. It 
should have some rest before being set again to work. 
During this rest, it collects in its* glands material for 
making a fresh supply of gastric juice. Eating between 

2. What is dyspepsia? Why not always avoidable? What is said 
concerning it in the majority of cases ? Most frequent cause ? 
Other causes? What is said concerning dyspepsia in those who live 
in cities? Concerning ease of cure?i 

3. Proper time between meals ? Exceptions ? What does the 
stomach collect during rest ? Why is eating between meals injurious ? 



PROPER TIME FOR MEALS, 12^ 

tneals keeps the stomach at work all the time, and it 
is not ready to do its duty properly when the meal- 
time comes. 

4. Meals should be taken at Regular Hours. — Three 
meals a day are sufficient, and many persons do better 
with two. Their regularity is of more importance than 
their number. The stomach, like the rest of our organs, 
soon forms habits, and only works with comfort when 
they are not interfered with. A little before the usual 
time of eating, we begin to feel an appetite, which grad- 
ually increases to a pleasant degree of hunger. If a man 
keeps at his work instead of heeding this hint, his whole 
system becomes run down from want of nourishment. 
His stomach itself is unable to secrete properly, and 
when at last he sits down to eat, utterly tired out, he 
has no appetite, and his meal is probably followed by a 
fit of indigestion. 

A heavy meal should not be eaten within two hours 
of going to bed. The presence of much food in the 
stomach, is very apt to cause troubled sleep. 

5. Meals should be Eaten Slowly and with Pleasant 
Surroundings. — The dinner-table should be the scene of 
a cheerful gathering, and merry talk. To bolt a meal 
in gloomy silence, thinking of one's work or worries, 
is not only bad manners, but bad hygiene. Talking of 
unpleasant things is often necessary, but should always 
be put off until an hour or two after dinner, when one is 
in much better condition to meet annoyances. 

4. Proper number of meals ? Why should they be taken at regular 
times ? What happens if a man allows his business to postpone a 
meal much beyond the proper time ? What is said concerning eating 
before bedtime ? 

5. What is said concerning the dinner-table ? About eating while 
thinking of work or worry ? About talking of unpleasant things ? 



126 PROPER AMOUNT OF FOOD. 

6. Some Rest should be taken before Eating^. — When 
the mind or body is greatly tired, the digestive organs 
will not act properly. A man engaged in any laborious 
business should therefore take his dinner after he has 
finished his day's work, and had at least half an hour's 
rest. If he come straight from his office to the table, 
and return there directly after eating, he will, in the 
long-run, injure his health. 

The day's work of a child should finish early, and be 
followed, after an hour's recreation, by dinner. If there 
is an afternoon session at school, the work should be of 
a kind calling for little mental effort ; for example, writ- 
ing or drawing. 

7. Food should be Eaten Slowly. — This ensures its 
proper mastication and thorough mixture with the 
saliva (p. io6). Thus the work of the stomach and other 
digestive organs is lightened. 

Moreover, rapid eating is very apt to lead to over- 
eating. Too much food is swallowed before enough 
has been absorbed to lead to diminution of the sensa- 
tion of hunger. 

8. The Proper Amount of Food varies with age, work, 
and climate. A person who has done growing, needs 
only enough to make good his daily waste, while a 
child should have something over, to supply materials 
for growth. In warm weather, less food is required than 
in cold, because less material has to be oxidized in the 

6. Why is it unwise to eat when very tired ? When should a man 
whose business is fatiguing dine? Why? What is said concerning 
the day's work of a child? Of afternoon session at school? 

7. Why should we eat slowly ? How is it that rapid eating may 
lead to over-eating? 

8. Conditions affecting proper amount of food ? Need of an adult ? 
Of a child? Influence of weather? What is a safe guide ? What is 



THE PROPER DIET. 12/ 

body (p. 82) to keep up the animal heat. If food be 
eaten slowly, the natural appetite is, in health, a safe 
guide. Those who injure themselves by over-eating, are 
not the workers who come to their meals hungry, but the 
indolent who, having little appetite, stimulate their pal- 
ates by highly flavored food, to enable them to eat what 
they have not earned, and their bodies do not want. 

An over-distended stomach is not merely injured it- 
self, but interferes with the heart and lungs. It pushes 
the diaphragm up against them and impedes their move- 
ments. Hence result feelings of oppression in the chest, 
shortness of breath, and faintness. Palpitation of the 
heart may also be produced : it is frequent in that kind 
of dyspepsia which is accompanied by accumulation of 
gas in the stomach. 

9. A Proper Diet contains both Animal and Vegetable 
Foods. — The teeth of a purely flesh-eating animal, as a 
tiger, are constructed only for tearing and cutting. 
Those of a vegetable-eater, as a cow, are very broad 
and constructed for grinding, except a few in front for 
cropping grass. Man*s teeth are half-way between the 
purely flesh-eating and purely vegetable-eating kind. 
Their structure shows that our proper food is both 
animal and vegetable. 

This is also proved by the fact that some of the 
digestive liquids found in the human alimentary canal 
are, like the saliva (p. 106), especially fitted to digest 



said concerning those who injure themselves by over-eating? Conse- 
quences of an over-distended stomach? What is said concerning 
palpitation of the heart ? 

9. Teeth of a purely flesh eating animal ? Of a vegetable-eater ? Of 
man ? What does their structure show ? How is this also proved ? 
When should less animal food be taken ? 



128 INFLUENCE OF WATER ON DIGESTION. 

Starch, which is the chief food - stuff in vegetables ; 
while others, as gastric juice (p. 113), are adapted to 
digest albumen, which is scarce in vegetables but abun- 
dant in most animal foods. 

In warm weather, when the body easily keeps up its 
animal heat, it is not well to eat much animal food. 

10. Drinking much Water during a Meal is Injurious. 
— The gastric juice acts well only in warmth, and a 
glass of cold water cools the stomach very much, 
and for a considerable time. Cold, also, drives the 
blood out of the mucous membrane, just as it would 
out of the skin. This stops or diminishes the action 
of the glands, which can only pour out abundant gastric 
juice when they are richly supplied with blood. If 
water be taken slowly, and only a few mouthfuls at a 
time, a much smaller quantity will satisfy the thirst, 
than if a glassful be taken at a draught. Also, the 
stomach is not enough cooled, at any moment, to inter- 
fere with digestion. Moreover there is a limit to the 
amount of water which the coats of the stomach will 
quickly absorb. Any more than that will be left over 
and make the gastric juice too weak to work well. 

About a single glass with a meal in cool weather, and 
two glasses in warm, is a proper quantity. 

In warm weather or after heating exercise it is well to 

assuage thirst at least half an hour before going to table, 

so that the water may be absorbed before the stomach 

is called upon to digest. 

10. What is necessary in order that the gastric juice may act 
well ? What is the effect of drinking a glass of ice- water? How does 
cold act on the blood in the mucous membrane ? What is the con- 
sequence as regards the glands of the stomach ? Why should water 
be drunk slowly ? The proper quantity with a meal ? Why assuage 
thirst some time before eating? 



ACTION OF COLD ON THE DIGESTIVE ORGANS. 1^0 

11. Exposure of the Skin to Cold often causes Disease of 
the Digestive Organs. — Every one knows that eating 
certain things, as unripe fruit, is apt to cause colic and 
diarrhoea. But a more frequent cause of these com- 
plaints is insufficient clothing. A man goes out on a 
summer morning with no cotton or woollen under-gar- 
ments, gets very hot at his day's work, comes home 
tired, and not able to withstand any extra strain on his 
organs. By way of becoming cooled and refreshed, he 
sits, with no extra clothing, in a draught. This chills the 
skin unduly, and the blood driven from it (p. 78) col- 
lects in internal organs in excessive quantity. A com- 
mon result is that the person feels chilly and uncom- 
fortable before going to bed, and is awakened in the 
night suffering from colic and diarrhoea. Diarrhoea is 
nearly always due to excessive secretion by the mucous 
membrane lining the bowels. This being inflamed 
secretes excess of watery liquid, like membrane lining 
the nose in a ** cold in the head." In both cases watery 
matter that ought to have been carried off by the skin is 
driven back to the interior. Draughts should always be 
avoided, but especially if the underclothing be damp 
with perspiration. Its rapid evaporation, by cooling the 
skin (p. 66) very fast, much increases the danger. If, 
in such circumstances, you have to sit in a current of 
air, throw an extra wrap around you, at least until the 
clothes next the skin have become dry. You will thus 
gain your end of getting to feel cool, nearly as soon as 

II. What is apt to result from eating unripe fruit? What is a 
more common cause of colic? Example? To what is diarrhoea 
directly due ? When should draughts be especially avoided ? Why ? 
What should be done if you cannot avoid sitting in a draught when 
perspiring? 



I30 ACTION OF ALCOHOL ON THE DIGESTIVE ORGANS. 

if you neglect this precaution, and with much less 
danger. 

12. The Large Intestine should be trained to empty 
itself once a day, at a regular hour. Neglect of this 
leads to the retention of injurious substances in the 
body. 

13. The Action of Alcoholic Drinks on the Digestive 
Organs is sucli as to frequently cause disease. In some 
cases this is due to a general slow poisoning of all parts 
of the body, enfeebling it and rendering impossible the 
healthy activity of any organ. Two digestive organs 
are, however, especially apt to be attacked by alcoholic 
disease. They are the stomach and the liver, 

14. The Action of Alcohol on the Stomach is first to 
cause its mucous membrane to become overgorged with 
blood, or, in medical language, congested. If the dose be 
not very large or soon repeated, this passes off, as the 
alcohol is absorbed and carried off by the blood to 
work mischief elsewhere. 

But repeated tippling keeps the stomach in this 
congested state. Instead of being allowed a period of 
rest before every meal, it is kept excited all the time 
and very soon becomes inflamed. Appetite is lost or 
replaced by nausea; the stomach, accustomed to the 
powerful alcoholic stimulant, does not pour out gastric 
juice when less stimulating food enters it, and dyspepsia 
is the consequence. 



12. What is said concerning the large intestine ? 

13. Action of alcoholic drinks on the digestive organs ? To what 
sometimes due ? What digestive organs are especially apt to be 
injured by alcohol? 

14. First action of alcohol on the stomach ? What follows if a 
fresh dose be not soon taken? Effect of repeated tippling? 



ACTION OF ALCOHOL ON THE STOMACH, I3I 

For a time, a person in this condition finds that another 
glass of spirits or wine creates appetite and, by exciting 
the stomach to secrete, promotes digestion. So he falls 
daily more and more into the habit of drinking. The 
consequence is that the stomach at last ceases to be 
able to make gastric juice at all. The usual glass now 
fails to produce appetite, and food if swallowed is not 
digested. Unless a very strong effort be made to break 
the habit, and skilful treatment be long employed to 
get the stomach back into a healthy state, a man in this 
condition is sure to die a drunkard. 

15. A Single Large Dose of Alcohol or of a drink con- 
taining it frequently irritates the stomach so much as to 
cause vomiting. This has saved the lives of many fool- 
ish people. Occasionally a very large dose paralyzes 
the stomach for a while, so that it does not absorb; 
this is sometimes seen when a man, for a bet, undertakes 
to drink a bottle of whiskey in a few minutes. If his 
stomach does not reject it, he often appears unaffected 
for half an hour or so: then suddenly falls down 
drunk, and often dies in a short time. This occurs 
when the stomach, having begun to recover from the 
first shock, suddenly commences to absorb the alcohol. 

16. The Action of Alcohol on the Liver. — All the blood 
which flows through the mucous membrane of the 
stomach goes straight to the liver, before it is carried to ^ 
any other organ of the body. This blood of course takes 

Explain. Consequences ? Why is a tippler apt to fall more into the 
habit ? Consequences ? 

15. Usual action of a large dose of alcohol on the stomach? 
Occasional result ? Example ? 

16. Where does blood leaving the stomach go next? What might 
we expect as regards the result on the liver of alcohol-drinking^? 



ip ACT/OAT OF ALCOHOL ON THE LIVER. 

with it whatever it has absorbed from the stomach. It 
is, therefore, not strange that the liver often becomes 
diseased from a man's taking alcoholic drinks. They 
cause a great overgrowth of the connective tissue (p. 13) 
of the liver, giving rise to what is known ^% fibrous degen- 
eration. All the true liver-substance is crushed and 
killed, and what remains is a shrunken, hard rough 
mass, well known to physicians as '^ hob-nailed," or 
'^ gin-drinker's liver." 

A liver in this condition cannot, of course, secrete bile 
properly, and thus digestion is imperfect. 

In still another way, the nourishment of the body is 
very seriously affected. Besides making bile, the liver 
has another duty. This is to take up from the blood 
the sugar (much of it made from vegetable starch, p. 108) 
which the blood has absorbed from the stomach or in- 
testines, and turn this sugar back into a kind of animal 
starchy which is more fitted to nourish the muscles and 
several other organs. This animal starch is then returned 
to the blood to be carried over the body. A diseased 
liver cannot perform this duty, and many organs are in 
consequence ill nourished. 

What is fibrous degeneration? Gin-drinker's liver? Result as re- 
gards digestion ? Another use of the liver besides making bile ? 
What becomes of the animal starch made in the liver? Result when 
liver is diseased ? 








PLATE IV.-THE CHIEF ARTERIES AXI) YEIXS OF THE BODY. 



EXPLANATION OT' PLAl'E IV. 

The Cibculatory Organs. 

The arteries (except the pulmonary) and the left side of the hear! 
are colored red; the veins, (except the pulmonary) and the right half 
of the heart blue: on the limbs of the left side the arteries are omitted 
and only the superficial veins are shown. 

1. Aorta, near its origin from the left ventricle of the heart. 

2. Lower end of aorta. 

3. Iliac artery. 

4. Femoral artery. 

5. Popliteal artery; the continuation of the femoral which passes behind the 

knee-joint. 

6. 7, The main trunks (anterior and posterior tibial arteries into which the 

popliteal divides). 

8. Subclavian artery. 

9. Brachial artery. 

10. Radial artery. 

11. Ulnar artery. 

12. Common carotid artery. 

13. Facial artery. 

14. Temporal artery. 

15. Eight side of Heart, with superior vena cava joining it above, and inferior 

vena cava (16) passing up to it from below. 

17. Innominate vein, formed by the union of subclavian and jugular veins. 

The right and left innominate veins imite to form the superior cava. 

18. Left internal jugular vein. 

19. Axillary vein. 

20. Basilic vein. 

22. Cephalic vein. 

23. Radial vein. 

24. Ulnar vein. 

25. Median vein. 

26. Ihac vein. 

27. Femoral vein. 

28. Long saphenous vein. 

29. The kidney; attached to it are seen the renal artery and vein. 

30. Branches of the pulmonary arteries and veins in the lung. 



CHAPTER XIII. 

THE CIRCULATION OF THE BLOOD. 

1: The Circulation. — Blood is not allowed to lie at rest 
in any part of the body. It is kept all the time moving 
round and round, from organ to organ, through a set of 
tubes, the blood-vessels. This regular flow of the blood 
is named the circulation. 

2. The Use of the Circulation. — If blood which had 
been enriched by the absorption of nourishment from 
the alimentary canal should remain stationary, the mus- 
cles and brain would be starved. If blood in the skin 
and that in deeper parts did not change places, the skin 
would become too cold, and the inside of the body too 
hot (p. 77). If the blood in a muscle were not kept 
moving on, and fresh blood taking its place, it would 
soon become so loaded with waste matters from the 
working muscles that it would poison them. It has to 
be carried off to organs (the lungs, Chap. XV., and 
kidneys. Chap. XVII.) in which these injurious matters 
are separated from it, and it is thus made again ready 
for use. By means of the circulation, then, the blood 
flows through every organ in turn; here becoming rich 

1. What is the circulation of the blood ? 

2. How might blood have nourishment in it and yet brain and 
muscles be starved ? What would happen, as regards the heat of the 
body, if the blood were not kept flowing through the skin ? How 
might the blood in a muscle poison it? What organs separate waste 
substances from the blood ? What is accomplished by the circulation ? 



134 THE ORGANS OF CIRCULATION. 

in foods, there feeding the organs; here warmed, and 
there cooled; here loaded with wastes, and there puri- 
fied. Thus by the flowing blood, every part is cared for. 

3. The Organs of Circulation are the heart, the arteries^ 
the capillaries, and the veins. The heart is a hollow mus- 
cle which squeezes the blood on, and keeps it moving. 
The arteries carry blood from the heart and distribute 
it over the body. The capillaries are very fine tubes 
with very thin walls, into which the arteries of every or- 
gan pour their blood. The veins take up blood from 
the capillaries and carry it back to the heart. 

4. The Blood, as every one knows, is a red liquid which 
is very widely distributed over the body, since it flows 
from any part of the surface when the skin is cut 
through. There are very few portions of the body 
into which blood is not carried. The outer layer of 
the skin (Chap. VI.), the hairs and nails, the hard parts 
of the teeth, and most cartilages contain no blood; 
these non-vascular tissues are nourished by liquid which 
soaks through the walls of blood-vessels in neighboring 
parts. 

5. Arterial and Venous Blood. — Although all blood is 
red, it is not all the same tint of red. In nearly all ar- 
teries, the blood, just sent out of the heart, is bright 
scarlet; such blood is named arterial blood. In nearly all 
veins, the blood, which has just flowed through the cap- 
illaries of some organ, is of a dark purple-red color; 
such blood is named venous blood. 

3. Name the organs of the circulation. What is the heart ? What 
are the arteries ? The capillaries? The veins ? 

4. Distribution of blood in the body ? Portions which get no 
blood? How are the non-vascular tissues nourished ? 

5. What is arterial blood ? Venous ? 



THE BLOOD. 



^35 



6. The Corpuscles of the Blood. — Fresli-drawn blood is, 
to the unaided eye, a uniform red liquid. But a micro- 
scope shows it to consist of a colorless liquid, the blood- 
plasma^ in which float vast numbers of tiny solid parti- 
cles, named the blood-corpuscles (Fig. 35). 




Fig. 35. Blood-corpuscles, magnified. At A the corpuscles are shown as seen 
when magnified four hundred diameters. The red corpuscles have adhered to- 
gether by their flat sides, as they usually do soon after a drop of blood has been 
drawn. At a are seen colorless corpuscles. B^ red corpuscles, very greatly mag- 
nified, seen in full face. C, the same seen edgewise. D. the same, adhering by 
their flat faces. F^ G, H, colorless blood-corpuscles, very much magnified. 



A few of the corpuscles are colorless and irregular in 
form (7^, G, ZT, 7), but by far the greater number are 
faintly colored. Seen by itself, each one looks pale yel- 
low; but a number crowded together appear red. 

6. What does a microscope show blood to consist of? Color and 
form of most of the corpuscles? Name? Number? Why is blood 
red ? How may it be made yellow ? 



136 THE BLOOD CORPUSCLES. 

Hence they are called the red corpuscles^ {B, C, D), In 
blood, the corpuscles are so closely packed that there 
are more than five millions in a single drop. It is this 
which makes the blood so red; if you dilute a drop of 
blood with a teaspoonful of water, or spread it out very 
thin on a piece of glass, it appears yellow. 

7. The Shape of the Red Corpuscles is that of thin circu- 
lar disks, a little hollowed out on each of their larger 
surfaces. If you made a piece of dough into a round 
cake, an inch across and a quarter of an inch thick, and 
then pressed it between thumb and finger so as to make 
a slight hollow on each side, you would have a very good 
model of a red blood-corpuscle. It would, however, be 
thirty-two hundred times broader and thicker than the 
real corpuscle. Put in another way, we may say that 
three thousand two hundred red corpuscles placed in a 
line, and touching one another by their edges, would 
make a row one inch in length; and twelve thousand 
eight hundred, piled one on another, would make a col- 
umn an inch in height. 

8. The Red Corpuscles of other Animals. — The red cor- 
puscles of most mammalia (p. 9) resemble those of man 

/Z\ r~~~^--^ in being: circular pale 

^'"^^-J/Ox iiJ-ri/\\ x"*^-^ ) yellow disks sliofhtly 

N^^jPj /L' A y hollowed on each side; 

^-^ those of camels and 

C^;^^^ dromedaries, however, 

Fig. 36.— Red corpuscles of the frog. are OVal. The blood- 

corpuscles of dogs are so like those of man in size that 

7. Shape of the red corpuscles ? Illustrate. What is said of their 
.size ? 

3. How do the red corpuscles of most mammalia resemble man's ? 



BLOOD-PLASMA. 137 

they cannot be readily distinguished; but in most cases 
the size is sufficiently different to enable a safe opinion 
to be formed, with a little pains. This fact has often 
been used to further the ends of justice, in determining 
whether spots of blood on the clothes of a suspected 
murderer were really due to the cause assigned by him. 
The red blood-corpuscles of birds, reptiles, amphibians, 
and fishes, cannot be confounded with those of man, 
since they are oval and contain a little mass in the cen- 
tre, which pushes out their sides and makes them pro- 
ject, instead of being hollowed. 

9. The Use of the Red Corpuscles is to carry oxygen over 
the body. When blood flows through the lungs, these 
corpuscles take oxygen (Chap. XV.); as it flows through 
other organs they give up that gas to them. When the 
corpuscles are laden with oxygen their color is bright 
red, if a number of them be seen closely packed to- 
gether; and when they have given up their oxygen, it is 
dark red. The different quantity of oxygen in the red 
corpuscles, is thus the reason of the different colors of 
arterial and venous blood. 

10. The Blood-Plasma consists of water with a good 
many things dissolved in it. The most important of 
these are (i) albumens; (2) sugar; (3) minerals. The 
plasma has also floating in it many very small drops of 



Exceptions? How may they be distinguished in most cases? How 
has this been used to further the ends of justice ? Describe the red 
corpuscles of birds, etc. 

9. Use of the red corpuscles ? When do they receive oxygen ? 
When give it up? How does oxygen affect their color? Why do 
arterial and venous blood differ in color ? 

10. Of what does blood-plasma consist ? The most important 
things dissolved in it? Floating in it? What does the plasma con- 
tain in addition to nourishing substances ? 



138 THE CLOTTING OF BLOOD. 

fat. In addition to these nourishing substances, the 
blood which flows away from muscle or gland or brain 
contains some waste substances, which it is carrying off 
to the lungs or kidneys for removal from the body. 

11. The Clotting or Coagulation of Blood. — When blood 
is first drawn from the living body it is perfectly liquid, 
flowing in any direction as easily as water. Very soon 
it becomes thick and sticky, like a red syrup; and at the 
end of five or six minutes it *^ sets" into a stiff jelly, which 
sticks to the cup or basin in which the blood is contained, 
so that the vessel may be turned upside down without 
spilling a drop. This alteration of the blood is named 
clotting or coagulation. It is due to a change of some of 
the dissolved albumens of tha blood, into a solid sub- 
stance named fibrin. 

If the jelly be kept for half an hour or so, it shrinks 
and squeezes out a liquid named serum. The solid part 
floats in the serum and is named the clot, 

12. The TJse of Coagulation is to save us from the risk of 
bleeding to death from wounds. So long as the blood is 
flowing in healthy living blood-vessels, no fibrin forms in 
it, and it does not clot. But as soon as blood gets out- 
side of the vessels, or whenever their lining is injured, 
clotting takes place. In this way, the ends of the 
small blood-vessels in a cut finger are soon clogged up, 
if we can only stop the flow for a little and give time 
for a clot to form in them. 



11. What is the consistency of fresh blood? What changes occur 
in it during the first five or six minutes after it is drawn ? What is 
the solidifying of the blood called ? To what is it due ? What is 
serum ? What is the clot ? 

12. Use of coagulation ? When does it not occur ? When does it 
take place? Why does a cut finger stop bleeding after a short time? 



THE HEART. 



139 



13. The Heart (Fig. 37) resembles a pear in form, and 
is placed in a slanting position inside the chest, with its 
smaller end downwards. It lies just above the diaphragm 
(Fig. 2), and behind the lower two-thirds of the breast- 
bone. Its upper end, or base (so called because it is the 




Fig. 37. — The heart and the arteries and veins opening into it, seen from the 
front. The pulmonary artery has been cut short close to its beginning, i, right 
ventricle; 2. left ventricle; 3, root of the pulmonary artery; 4, 4', ^'\ the aorta; 5, 
part of the right auricle; 6, part of the left auricle; 7, 7', innominate veins joining 
the upper vena cava; 8, inferior vena cava; 9, one of the veins from the liver, join- 
ing the inferior vena cava. 

larger end, although the upper), projects a little to the 
right of that bone, and its lower end, or apex, a little 
to the left, where it may easily be felt beating by pressing 
with the finger between the cartilages (p. i8) of the 

13. Shape and position of the heart ? Where does its base project ? 
Where may it§ apex be felt beating? Its size ? 



I40 



THE PERICARDIUM, 




fifth and sixth ribs. A healthy heart is about the size 
of the clenched fist of its owner. 

14. Interior of the Heart. — When the heart is cut open 

(Fig. 2>^) it is found to 
be hollow. Its cavity is 
not single, but is sepa- 
rated into a right and a 
left chamber, by a parti- 

* ps tion which runs through 
it from base to apex. 
Each chamber consists of 
an upper division, Au^ 
Au\ called an auricle j 

Fig. 38.— Diagram of a section through and a lower divisiou, V^ 
the heart. Au^ Au\ auricles; F, F^ ven- , ' 7 r^ 
tricles; cj, upper hollow vein; ^z, lower hoi- K, named 2l VentriCU, On 
low vein; P, pulmonary artery; pd^ps^ pul- 
monary veins; A^ aorta. Between each each Side there IS a large 
auricle and the corresponding ventriclie, 

and at the mouth of pulmonary artery and opening; between the au- 

aorta, the valves which control the direc- ^ ^ 

tion of the blood-flow are seen. j-j^le and Ventricle ; but 

there is no direct passage from the cavities on the right 
side of the heart to those on the left. 

The divisions of the heart are, therefore, right auricle^ 
right ventricle^ left auricle^ left ventricle. 

15. The Pericardium. — The heart is surrounded by a 
loosely fitting case or bag, named the pericardium. The 
inside of this bag and the outside of the heart are covered 
by a very smooth membrane. In the space between the 
heart and its case there is in health a small quantity of 



14. How is the cavity of the heart divided ? Of what do its cham- 
bers consist ? What is said of communication between auricles and 
ventricles of the same and of different sides ? Name the divisions of 
the heart? 

15. What is the pericardium ? What is found inside it and outside 
the heart ? In the space between ? Use ? 



THE VESSELS OPENING INTO THE HEART I4I 

liquid, which makes the surfaces slippery, and allows 
the heart to contract or expand with very little friction. 

16. The Vessels opening into the diflferent Divisions of 
the Heart (Fig.38). — Veins bring back blood to the heart, 
and open into the auricles. Arteries carry blood from 
the heart, and start from the ventricles. 

The veins pouring blood into the right auricle are 
named the upper {cs) and the lower (ci) hollow veins, or vence 
cavcB. They got this name because after death, when 
most veins either collapse or are filled with blood, 
these are often found distended and empty. 

One artery, F, springs from the right ventricle, and 
carries to the lungs the blood brought to the right side 
of the heart by the hollow veins. It is named the pul- 
monary artery. 

The veins, pd, pSy which open into the left auricle are 
named the pulmonary veins. They bring blood from the 
lungs. 

One artery, A, arises from the left ventricle ; it is 
named the aorta. As it proceeds from the heart it di- 
vides, like the trunk of a tree, and at last its branches 
reach every organ of the body except the lungs. 

17. The Beat of the Heart. — The heart relaxes about 
seventy times a minute, and takes blood from the veins; 
it contracts after each relaxation and forces blood into 
the arteries. This regularly alternating expansion and 
contraction, is known as the beat of the heart. 



16. Function of veins? Place of opening into heart? Function 
and place of opening of arteries ? What veins bring blood to right 
auricle ? Why so named ? What is the pulmonary artery ? What 
veins open into left auricle ? Whence do they bring blood ? What 
is the aorta ? What becomes of its branches ? 

17. Describe the beat of the heart ? 



14^ VALVES OF THE HEART. 

18. The Valves of the Heart only permit blood fe ffow 
through it in one direction. When the heart is expand- 
ing and receiving blood, none flows back into the ven- 
tricles from the arteries, because the semthmdr [half- 
moon-shaped^ valves^ at the mouths of the pulmonary' 
artery and aorta, block the road. They will open out- 
wards from the heart, and let blood Jiow f7'077t the ventri- 
cle, but they will not open the other way and let blood 
flow back from the artery into the heart. 

When the heart dilates, it fills with blood from the veins. 
Then a ring of muscle round the mouth of each vein close 
to the heart, contracts and narrows the opening. Next 
the auricles contract, and the only way each can drive 
the blood collected in it, is into the ventricle of the same 
side. Immediately afterwards the ventricles contract 
and squeeze on the blood which has collected in them. 
This blood would go back into the auricles but for the 
valves which lie in the openings between each auricle 
and its ventricle, and only open towards the ventricle. 
As soon as any blood tries to flow back, the valves close 
and block the road, so the only way the contracting ven- 
tricle can send its blood is on into the arteries. 

The valve between the right auricle and ventricle is 
named the tricuspid or three-pointed valve. That between 
the left auricle and ventricle is the bicuspid or two- 
pointed valve. It is sometimes named the mitral valve, 
from being shaped like the two points of a bishop's mitre. 

i8. Use of the valves of the heart ? Position of semilunar valves? 
Action? How are the mouths of the veins narrowed before the auri- 
cles; contract ? Where does each auricle pump its blood? What hap- 
pens after the auricles have contracted ? Why does not blood flow- 
back in the auricles when the ventricles contract ? Where do the 
ventricles pump blood ? Where is the tricuspid valve ? The mitral ? 



THE COURSE OF THE BLOOD-FLOW. 



143 




19. The Course of the Blood-Flow. — Any portion of 
blood, starting from any chamber of 
the heart returns there after a short 
time, and starts from it again. This is 
why the blood-flow is called a circula- 
tion. The return is not direct; blood 
leaving the left side of the heart comes 
bcick first to the right, and blood start- 
ing from the right side returns first to 
the left. 

How this occurs may be easily un- 
derstood by examining Fig. 39, which 
represents, in a general way, the heart 
and blood-vessels. Starting from the 
/^//ventricle,/, blood flows along the 
aorta, ;//, and its branches, to all parts 

, ^1 1 ^ rj^\ 1 1 the blood-flow. Z>. rig-ht 

except the lungs. ^ 1 hese branches auricle of ihe heart ;%-, 

, . , 11 1 right ventricle; />, pul- 

end in the very small and very monary anery and its 

"^ . branches; «. tlie capil- 

numerous capillaries, /, of the mus- laries of the lun^s; c, 

the pulmonary veins; e^ 

cles, and skin, and mucous membranes, the left auricle of the 

heart; f. the left ventri- 

and so forth. From these capillaries cie; m, the aorta, di- 

^ viding' into the smaller 

the blood is collected by veins, which arteries; / the capilla- 

-^ ' nes of all the organs 

unite to make the hollow veins, k, teinT b'ingrnT'.o''' fhe 
which pour it into the ;7^/// auricle. IifV«s"tf''t°,°e' bTy 

T-. 'i^ -i*^' i.^ '-Ui. but the lungs; h, the 

From right auricle it is sent to right pericardium. 
ventricle, and thence by the pulmonary artery and its 

19. Why is the blood flow called a circulation ? To which side of the 
heart does blood which has last left the right ventricle first return ? 
Starting from the left ventricle, describe the course taken by the 
blood until it gets back there. How often does the blood come bacl^ 
to the heart in making a complete circulation ? 



FiG. 39. — Diagram of 
he circulatory organs, 
to show the course of 



♦Some branches of the aorta carry a little blood to the lungs: but for the pur, 
pose of getting a general idea of the blood flow this may be neglected. 



144 SYSTEMIC AND PULMONARY CIRCULATIONS. 

branches, ^, to the lungs. There it flows through the 
pulmonary capillaries, a, and is collected from them 
into the pulmonary veins, r, which convey it to the left 
auricle; thence it flows to the left ventricle, and com- 
mences its round once more. 

The valves of the heart only let the blood flow in 
the direction of the arrows in Fig. 39. If you start at 
any point in that figure and follow along in the direc- 
tion pointed by the arrows, you will find that the blood 
cannot flow back at once, to the side of the heart it 
started from. To make a complete circulation, it twice 
leaves, and twice returns to, the heart. 

20. The Systemic and Pulmonary Circulations. — To get 
from the left side of the heart to the right, the blood 
must flow through the arteries, capillaries, and veins of 
the body in general. This flow, from left ventricle to 
right auricle, is often named the syste77iic circulation. To 
get from the right side of the heart to the left, blood 
must flow through the arteries, capillaries, and veins of 
the lungs. This flow, from right ventricle to left auri- 
cle, is often named i\\t pulmonary circulation. It is clear, 
however, that neither is a circulation in the proper mean- 
ing of the word, for after completing it, the blood is 
not back again at the place it started from. In order 
that it may be, it must go through both these circula- 
tions. 

21. Illustration. — We may compare the blood- supply 
of the body to the water-supply of a city. The left side 
of the heart answers to the reservoir, and the arteries to 

20. What is the systemic circulation? The pulmonary? Why is 
neither a circulation, strictly speaking ? 

21. Compare the blood-supply of the body to the water-supply of a 
city. In what respects is it essentially different ? What would have 



THE PULSE, 145 

the water-mains. They begin at the heart, and are very 
much branched except close to it. The aorta answers 
to the main aqueduct leaving the reservoir, and there 
single, but giving off branches and becoming more and 
more divided the farther we follow it. At last the water- 
main ends in numerous but very much smaller tubes to 
supply various houses, as the branches of the aorta sup- 
ply different organs. 

The course of the blood differs, however, essentially 
from that of the water-supply of a city, for the used 
water does not return to the reservoir, whereas the 
blood is carried back to the heart. Instead of having a 
^ large supply of liquid stored up as in a reservoir, there 
is at any one time only quite a small amount in the 
heart, but this is steadily replaced by the inflow through 
the veins as fast as it is carried off by outflow through 
the arteries. 

If the water used in the city were all carried back 
through the sewers (answering to the veins), to another 
reservoir placed beside the one it started from ; and thence 
w^ere carried by a different set of pipes (the pulmonary 
artery and its branches) into a purifying apparatus; and 
then back to the first reservoir, the whole process would 
be much like the circulation of the blood. The two reser- 
voirs would represent the heart, which is double, and the 
purifying apparatus would represent the lungs. 

22. The Pulse. — The arteries are as elastic as rubber 

tubing. Every time the heart beats and forces blood 

into them, their walls are stretched to make room for it. 

When an artery lies near the surface, this stretching 

to be done with the used water to make the illustration complete ? 
What would represent the lungs ? 
22. What is the pulse ? 



14^ 



"THE CAPILLARIES. 



can be felt through the skin. It is known as the pulse. 
The number of pulses in a minute, therefore, tells the 
rate at which the heart is beating. 




Fig. 40.— a small portion of the capillary network of the web between a frog's 
toes, as seen with a microscope, a, a small artery feeding the capillaries; r, r/, 
small veins carrying blood back from the latter. The arrows indicate the direc- 
tion of the blood-flow. 

23. The Capillaries (Fig. 40) are such tiny tubes that 
they cannot be seen without a microscope. Their vast 
number makes up for their small size; in most organs 

23. What is said of the size of the capillaries? Of their number? 
Illustrate. How does the blood do its work while flowing through 
ithem ? Illustrate. 



ARTERIAL' AND VENOUS-BLdOD VESSEL^. I47 

they are so closely packed that a pin's point cannot be 
inserted without wounding some of them. This is illus- 
trated when the skin is pricked. The blood in it is not 
lying loose but is flowing in capillaries. We cannot in- 
sert a needle deeper than the epidermis without wound- 
ing some of these capillaries and causing bleeding. 

It is w^hile flowing in the capillaries that the bloodi 
does its work. Their walls are so thin that nourishing; 
matters easily «oak through them to feed the organs;; 
and the waste matters of the organs readily pass 
through the walls of these tiny vessels into the blood. 

Imagine a piece of the finest net, with all its threads 
consisting of hollow tubes, and diminished one hun- 
dred times in size, and you will have some idea of the: 
fine jietworks formed by the capillaries in the various: 
organs. 

24. Which Vessels contain Arterial and which Venous: 
Blood. — As blood flows through the capillaries of the 
lungs, its red corpuscles take up oxygen from the air 
(Chap. XV.). The blood thus becomes bright red or ar- 
terial (p. 134). It flows, keeping this color, through the 
left auricle and ventricle of the heart, and along the 
aorta and its branches (the systefnic arteiHes)^ which con- 
vey it to the body in general. These arteries pour the 
blood into the capillaries of all organs except the lungs. 
As it flows through these systemic capillaries the blood 
gives up its oxygen to the organs and becomes dark- 
colored. It is then collected into the systemic veins, 
and, still of a dark color, is conveyed to the right auri- 
cle, right ventricle, and thence by the pulmonary artery 

24. In what vessels does the blood become arterial ? Through 

what part of its course does it keep its bright color? Where does 

4t lose it? Why? Describe its course until it becomes bright 



148 APPENDIX TO CHAPTER XIII. 

to the lungs, wlien it once more receives oxygen and 
becomes bright red. 

Thus the pulmonary veins differ from all other veins 
in containing arterial blood; and the pulmonary artery 
and its branches, from all other arteries in containing 
venous blood. The ancient anatomists accordingly named 
the pulmonary artery, the arterious vein. 

In Fig. 39, the vessels which convey venous blood are 
shaded. 

again. How do the pulmonary veins differ from all other veins ? 
The pulmonary artery and its branches from all other arteries ? 



APPENDIX TO CHAPTER XIII. 

The Blood. 

Many of the main facts pertaining to the structure and composition 
of blood may be easily demonstrated as follows: 

1. Kill a frog with ether (p. 46); cut off its head, and collect on a 
piece of glass a drop of the blood which flows out. Spread out the 
drop so that it forms a thin layer. Hold the glass up against the 
light, and examine the blood with a hand-lens magnifying four or 
five diameters. The corpuscles will be readily seen floating in the 
plasma. 

2. Wind tightly a piece of twine around the last joint of a finger; 
then, with a needle, prick the skin near the root of the nail. A 
large drop of blood will exude. Spread it out on a piece of glass and 
examine, as described above for frog's blood. The corpuscles will be 
seen floating in the blood-liquid, but not so easily as in frog's blood, 
since those of man are considerably smaller. 

3. Obtaining a large drop of human blood as above described (2), 
note {a) that as it flows from the wound it is perfectly liquid ; (b) 
that it is red and very opaque; {c) spread it out very thin on the glass; 
note that it then looks yellow when held over a sheet of white paper; 
{d) mix a similar drop with a teaspoonful of water in a wine-glass; 
note that the mixture is yellowish, or, if not, becomes so on further 
dilution. 

4. Place another large drop of human blood, obtained as above 
indicated, on a clean piece of glass. To prevent drying, cover by 
inverting over the drop a wine glass whose interior has been moist- 
ened with water. In four or five minutes remove the wine-glass and 
note that the blood-drop has set into a firm jelly. Replace the moist 



APPENDIX TO CHAPTER XIII. I49 

wine-glass, and in half an hour examine again. The blood will then 
have separated into a tiny red clot, lying in nearly colorless serum. 

5. If a slaughter house is accessible, the clotting of blood may be 
still better illustrated. Provide two large wide-necked glass bottles 
and a bundle of twigs. When the butcher bleeds an animal, collect 
in one bottle some blood, taking care that nothing else (contents of 
the stomach, for example, when the animal is bled, as is often done, 
by cutting off its head) gets mixed with it. Put this bottle aside until 
the blood clots, and carry it home with the least possible shaking. 
Next day the mass will exhibit a beautiful clot floating in serum. 
The latter will probably be tinted red, as the jolting in conveying the 
specimen from the slaughter-house shakes some of the red corpuscles 
out of the clot into the serum. 

6. In the other bottle collect blood and stir it vigorously with the 
twigs for three or four minutes. Next day this specimen will not 
have clotted, bjit on the twigs will be found a quantity of stringy 
elastic material (fibrin), which becomes pure white when thoroughly 
washed with water. 

7. Take some of the serum from specimen 5. Observe that it 
does not coagulate spontaneously. Heat it in a test-tube over a 
spirit-lamp; its albumen will then coagulate, like the white of a hard- 
boiled ^%%, and the whole will become solid. 

8. Place a small quantity of whipped blood (6) on a piece of plati- 
num foil. Heat over a spirit-lamp. After the drop dries it blackens, 
showing that it contains much animal matter. As the heating is con- 
tinued this is burnt away, and a white ash, consisting of the mineral 
constituents of the blood, is left. 

The Circulatory Organs. 

1. In the following directions ** dorsal'* means the side of the heart 
naturally turned towards the vertebral column, ''ventral" the side 
next the breast-bone; "right" and "left" refer to the proper right 
and left of the heart when in its natural position in the body; "an- 
terior" means more towards the head in the natural position of the 
parts; and "posterior" the part turned away from the head. 

2. Get your butcher to obtain for you a sheep's heart, not cut out 
of the bag (pericardium), and still connected with the lungs. Impress 
upon him that no hole must be punctured in the heart, such as is usu- 
ally made when a slaughtered sheep is cut up for market. 

3. Place the heart and lungs on their dorsal sides on a table in 
their natural relative positions, and with the windpipe directed away 
from you. Note the loose bag {peHcardiupi) in which the heart lies, 
and the piece of midriff {diaphragm) which usually is found attached 
to its posterior end. 

4. Carefully dissecting away adherent fat, etc., trace the vessels 
below named until they enter the pericardium. Be very careful not 
to cut the veins, which, being thin, collapse when empty, and may 
be easily overlooked until injured. As each vein is found stuff it 
with raw cotton, which makes its dissection much easier. 

a. The vena cava inferior: find it on the under (abdominal) side of 
the diaphragm; thence follow it until it enters the pericardium, about 



ISO APPENDIX TO CHAPTER XIIL 

three inches further up; to follow it in this part of its course, turn 
ithe right lung towards your left afid the heart towards your right. 

The vein, just below the diaphragm, may be seen to receive several 
large vessels, the hepatic veins. 

As it passes through the midriff, two veins from that organ enter it. 

b. Slip erior vena cava: seek its lo \ er end, entering the pericardium 
about one vnch above the entry of the inferior cava; thence trace it 
iUp to the point where it has been cut across; stuff and clean it. 

c. Between the ends of the two venae cavae will be seen the two 
right pulmonary veins, proceeding from the lung and entering the 
pericardium; clean and stuff them. 

5. Turn the right lung and the heart back into their natural posi- 
tions; clear away the loose fat in front of the pericardium, and seek 
and clean the following vessels in the mass of tissue lying anterior to 
ithe heart, and on the ventral side of the windpipe. 

a. The ao7'ta: immediately on leaving the pericardium this vessel 
gives off a large branch; it then arches back and ruils down behind 
the heart and lungs, giving off several branches on its way. 

b. The puhiionary artejy: this will be found imbedded in fat on the 
•dorsal side of the aorta. After a course, outside the pericardium, of 
:about an inch, it ends by dividing into two large branches (right and 
jleft pulmonary arteries), which subdivide into smaller vessels as they 
enter the lungs. 

c. Observe the thickness and firmness of the arterial walls as com- 
pared with those of the veins; they stand out without being stuffed. 

6. Notice, on the ventral side of the left pulmonary artery, the left 
pulmonary veins passing from the lung into the pericardium. 

7. Slit open the pericardic bag, and note its smooth, moist, glis- 
tening inner surface, and the similar character of the outer surface of 
the heart. Cut away the pericardium carefully from the entrances 
of the various vessels which you have already traced to it. As this 
is done, you will notice that inside the pericardium the pulmonary 
artery lies on the ventral side of the aorta. 

9. Note the general form of the heart — that of a cone with its apex 
turned towards the diaphragm. Very carefully dissect out the entry 
of the pulmonary veins into the heart. It will probably seem as if 
the right pulmonary veins and the inferior cava opened into the same 
portion of the organ, but it will be found subsequently (13, a) that such 
is not really the case. Note on the exterior of the organ the follow- 
ing points: 

a. Its upper flabby auricular portion into which the veins open, 
and its thicker lower ventricular part. 

b. Running around the top of the ventricles is a band of fat, an 
offshoot of which runs obliquely down the front of the heart, passing 
to the right of its apex, and indicating externally the position of the 
internal partition, or septtwi, which separates the right ventricle, 
which does not reach the apex of the heart, from the left, which 
does. 

10. Dissect away very carefully the collection of fat around the 
origins of the gre^t arterial trunks and that around th^ l3a.se of the 
ventricles. 



APPENDIX TO CHAPTER XIII. I5I 

11. Open the right ventricle by passing the blade of a scalpel 
through the heart about an inch from the upper border of the ventri- 
cle, and on the right of the band of fat marking externally the limits 
of the ventricles, and noted above (9, b), and then cut down towards 
the apex, keeping on the right of this line; cut off the pulmonary 
artery about an inch above its origin from the heart, and open the 
right auricle by cutting a bit out of its wall, to the left of the 
entrances of the venae cavse. On raising up by its point the wedge- 
shaped flap cut from the wall of the ventricle, the cavity of the latter 
will be exposed. 

a. Pass the handle of a scalpel from the ventricle into the auricle, 
and also from the ventricle into the pulmonary artery, and make out 
thoroughly the relations of these openings. 

b. Slit open the right auricle. Observe the apertures of the vencB 
cavcE, and note that the pulmonary veins do not open into this 
auricle. 

12. Raise up by its apex the flap cut out of the ventricular wall, 
and if necessary prolong the cuts more towards the base of the 
ventricle until the divisions of the tricuspid valve come into view. 

a. Note the muscular cord (not found in the human heart) stretch- 
ing across this ventricle. Also the prolongation of the ventricular 
cavity towards the aperture of the pulmonary artery. 

b. Cut away the right auricle, and examine carefully the tricuspid 
valve, composed of three membranous flexible flaps, thinning away 
towards their free edges; proceeding from near these edges are 
strong tendinous cords {chordcB tendi^ieie), which are attached at their 
other ends to muscular elevations {papillary muscles) of the wall of 
the ventricle. 

c. Slit up the right ventricle until the origin of the pulmonary ar- 
tery comes into view. Looking carefully for the flaps of the semilunar 
valves, prolong your cut between two of them so as to open the bit of 
pulmonary artery still attached to the heart. Spread out the artery 
and examine the valves. 

d. Each flap makes, with the wall of the artery, a pouch, opposite 
which the arterial wall is slightly dilated. The free edge of the valve 
is turned from the heart, and has in its middle a little nodule {corpus 
Arantii). 

13. Open the left ventricle in a manner similar to that employed 
for the right. Then open the left auricle by cutting a bit out of its 
wall above the appendage. Cut the aorta off about half an inch 
above its origin from the heart. The aperture between left auricle 
and left ventricle can now be examined; also the passage from the 
ventricle into the aorta, and the entry of the pulmonary veins into 
the auricle; and the septum between the auricles and that between the 
ventricles. 

a. Pass the handle of a scalpel from the ventricle into the auricle; 
another from the ventricle into the aorta; and pass also probes into 
the points of entrance of the pulmonary veins. Observe that no other 
veins open into this auricle. 

b. Note the great thickness of the wall of the left ventricle, as com- 
pared with that of the right ventricle or of either of the auricles. 



152 APPENDIX TO CHAPTER XI 11. 

c. Carefully raise the wedge-shaped flap of the left ventricle, and 
cut on towards the base of the heart, until the valve {t?iitral) between 
auricle and ventricle is brought into view; one of its two flaps will be 
seen to lie between the auriculo-ventricular opening and the origin of 
the aorta. 

Examine in these flaps their texture, the chordae tendineae, the 
papillary muscles, etc., as in the case of the right side of the heart 

(12). 

d. Examine the semilunar valves at the exit of the aorta; then cut- 
ting up carefully between two of them, examine the bit of aorta still 
left attached to the heart, and note the valves more carefully as de- 
scribed in 12, d, 

14. Examine a piece of aorta. Note that when empty it does not 
collapse; the thickness of its wall; its extensibility in all directions; 
its elasticity. 

15. Compare with the artery the thin- walled flabby veins which 
open into the heart. 



CHAPTER XIV. 

HYGIENE OF THE CIRCULATORY ORGANS. 

1. To Ensure a Healthy and Regular Circulation of the 
blood, the skin must be kept warm. Cold, we have 
learned (p. 72), contracts its blood-vessels and drives 
the blood elsewhere. This does no harm if it be only 
for a short time; indeed often does good. But a pro- 
longed chill of the surface is very apt to cause disease of 
some internal organ, by keeping it overfilled with blood, 
or congested, 

A blush is a brief healthy congestion of the skin of the 
face. It may be compared to the flushing of the mucous 
membrane of the stomach when gastric juice is being 
secreted. In each case, the temporary rush of blood to 
the part nourishes it. But continued overfulness of 
blood has an opposite effect. Too much liquid from 
the blood soaks through the walls of the capillaries, 
and the organ in which they lie becomes puffy and 
swollen. 

2. Taking Cold. — Congestion produced by a chill of 
the surface oftenest shows itself on some mucous mem- 
brane. If that lining the nose be attacked, it becomes 

1. What effect has the temperature of the skin on the circulation of 
the blood ? What is apt to result from a prolonged chill of the sur- 
face ? What is a blush ? To what compared ? Results of prolonged 
overfulness of blood ? 

2. Where do congestions due to cold most often occur? Describe 



154 TAKING COLD. 

swollen, and we have difficulty in breathing through the 
nostrils. It is also irritated, and so we sneeze (p. 174). 
Unless proper means be at once taken to stop the '' cold,'* 
the congested mucous membrane becomes inflamed. In 
that case, its vessels are not only gorged with blood, but 
the whole membrane is in a state of unhealthy activity. 
So far as its glands are concerned, this is shown by the 
unnaturally abundant watery mucus which runs from 
the nostrils. 

When deeper parts of the mucous membrane are 
attacked by " a cold," we cannot observe the details so 
easily. But they are much the same in all cases. Thus 
when the mucous membrane of the tubes which carry air 
into the lungs (p. 171) is the one attacked, we suffer from 
a '^ cold on the chest," or bronchitis. In this case we 
have difficulty in breathing, because the swollen mem- 
brane narrows the air-passages; we feel pain and irrita- 
tion in the chest; and we cough up abundant " phlegm" 
or unnatural secretion. 

If the " cold " attacks the mucous membrane of the 
stomach, we suffer from loss of appetite and from in- 
digestion, because the altered secretion fails to do its 
proper work. The production of diarrhoea by cold at- 
tacking the bowels has been already referred to (p. 129). 

3. To Avoid taking Cold, the essential things are to 
wear proper clothing, and, when perspiring, to guard 
against sudden cooling (Chap. VII.). If unavoidably 
exposed to conditions apt to cause a cold, the risk may 

the condition of the mucous membrane of the nose during a "cold in 
the head." That of the air-passages during a "cold on the chest." 
Results of a cold attacking the mucous membrane of the stomach ? 
Of the bowels ? 

3. To avoid taking cold what things are most necessary ? What 
should be done to prevent a cold, after exposure likely t,o cg.use qn^ \ 



HOW TO AVOID TAKING COLD. 1 55 

be much diminished by prudence. Try to get your skin 
warm and your sweat-glands active as soon as possible. 
Exercise is usually the best way to do this. When you 
feel chilled, and have some distance to go before you can 
reach a warm room or get extra clothing, it is wiser to 
run or walk or row, if possible, than to sit still and be 
driven. The muscular exercise will warm the skin. If 
obliged to keep on wet clothing, throw over it a dry 
wrap. This will prevent the wet garments from drying 
rapidly, and thus taking heat from the skin too fast 
(p. 66). As soon as possible rub the whole skin briskly 
until it is red and warm; then put on dry woollen cloth- 
ing. If your skin does not quickly warm when rubbed, 
take a warm bath, go to bed, and drink two or three 
large cups of hot weak tea or lemonade. If a warm bath 
cannot be had, put the feet in hot water. 

4. Articles of Dress should not Fit so Tightly as to Check 
the Blood-Flow. — Most large arteries lie deep, but many 
large veins are near the surface, just under the skin. 
The flow of blood in a vein is easily stopped by pres- 
sure, because the walls of the veins are thin and flabby; 
and when the vein leading from any organ is squeezed, 
the blood-flow from it is hindered. Thus congestion is 
produced. 

The veins most often impeded in their work by tight 
clothing, are those of the neck and leg. 

The chief veins bringing back blood from the head 
are the external jugular veins, which lie under the skin. 

What if the clothing is wet and cannot be at once changed ? What 
should be done as soon as you can change it ? What is the object of 
the exercise, baths, rubbing, etc.? 

4. How may tight garments produce congestion ? Which veins are 
most often compressed by articles of ordinary clothing? What are 
the external jugular veins ? What is apt to follow if they are com- 



^56 TIGHT GARTERS. 

one on each side of the neck. A tight collar or scarf 
compresses these veins and tends to cause congestion of 
the brain, dizziness, redness of the eyes, and a flushed 
face. 

The chief vein which brings back blood from the foot 
and the lower leg is named the long saphenous vein (PI. 
IV., 28). It begins on the inner side of the ankle, and 
runs to the top of the thigh. A tight garter compresses 
the saphenous vein, into which many other veins of the 
leg pour their blood, and thus checks the circulation in 
that part of the body. The results are deficient blood- 
flow in the feet. Congestions and inflammations, as 
chilblains^ more easily occur, and the feet are more apt 
to become cold, if the garter be very tight, the veins 
below it often get so gorged with blood that their walls 
stretch and form swellings, known as varicose veins. 
Varicose veins sometimes burst and cause dangerous 
bleeding; they very often so press and crush the tissues 
in their neighborhood as to cause inflammation and 
sores. The stocking-supporters now so commonly used, 
which attach the stocking to the waistband, are far 
better than ordinary garters. 

5. Muscular Exercise Promotes the Circulation of the 
Blood, not only because it quickens the beat of the 
heart, but because the contracting muscles drive along 
the blood in the veins. 

In the veins are numerous valves (Fig. 41), which open 
towards the heart and from the capillaries. Blood flow- 
pressed? What is the saphenous vein ? Describe its course. How 
does a tight garter affect the flow of blood in the leg? Results ? How 
ma}" varicose veins be produced ? Consequences of varicose veins? 

5. How does muscular exercise promote the blood-flow? How is 
blood prevented fi;om flowing back through the veins towards the 



THE VALVES OF THE VEINS, 1 57 

ing in the proper direction, A, from capillaries to heart, 

is not hindered on its road; but any back-flow in the 

opposite direction, B, is at once ^ 

checked by the closing of the valve, c Z^"^ h 

This you may easily observe on 

the back of the hand of any one ^ 

who is thin. Select a vein which has '^ //^ "^ '' 

no branches for an inch or more. Fig. 41.— Diagram to nius- 

. 11-1 \X2X^ the mode of action of the 

Press on its lower end, that is the valves of the veins. C, the 

capillary, H, the heart end of 

end nearer the fingers, so as to close the vessel. 
it. Then push the blood out of it by rubbing it with your 
forefinger in a direction towards the wrist. The vein 
will remain empty up to the place where the next higher 
branch joins it. At that place there is a valve, which 
will not allow blood to flow back into it. As soon as 
you remove the pressure from its lower end, however, 
the vein immediately fills, with blood brought to it from 
the capillaries of the fingers. We learn from this simple 
experiment that the valves of the veins allow blood to 
flow through the veins to the heart, but not from it. If 
the first vein you try the experiment with, does not be- 
have as it should, try another, for some of the veins on 
the back of the hand have branches entering their deeper 
sides, which you cannot see, and from which they be- 
come filled. 

When the muscles contract in length and swell in 
breadth (p. 35) they press on the veins near them. 
This pressure cannot drive blood back to the capillaries, 
on account of the valves in the veins. But it drives 
blood on from the veins towards the heart, and thus pro- 
capillaries ? How may we observe on the hand the action of the 
valves of the veins ? How do the muscles promote the circulation of 



158 CUTS AND WOUNDS. 

motes the circulation. When the muscles relax, the veins 
fill again; and then the next muscular contraction forces 
the blood inside them on towards the heart. In this 
way muscular exercise is a great help to the heart in 
keeping up the flow of blood. 

When you feel cold, a brisk walk or run, or, if the 
weather is too severe for outdoor exercise, indoor gym- 
nastics, will warm you sooner and better than sitting over 
a fire. This is especially the case with coldness of the 
feet. Toasting them over a fire is of little use. They be- 
come cold again almost as soon as you leave the fire. But 
a brisk walk or an active game will soon increase the cir- 
culation, and make the feet warm for the rest of the day. 

6. Cuts and Wounds. — If the wound be made by a clean 

sharp instrument and the bleeding is not great, press its 

edges together and hold them in place by a moderately 

tight bandage. The edges of a gaping wound may need 

to be held together by sticking-plaster; in other cases it 

does no good. Wounds which a single wider strip of 

plaster will not hold at all, may be nicely held together 

by separate narrow strips from J to f of an inch wide, 

according to the nature of the cut. Taking one, warm 

and fasten it on the farther side of the wound. Pull the 

loose end of the strip towards you and press the nearer 

lip of the wound against the farther one, then fasten the 

rest of the strip firmly down and hold it till it sets. 

Proceed in like way with the other strips. Ointments 

and salves are never necessary to promote the healing of 

a simple clean cut, and very often do harm. 

the blood ? How does this affect the heart ? Why is it better to 
warm yourself by exercise than by sitting over a fire ? 

6. What is the proper treatment for a " clean" cut? If its edges 
gape? How should sticking-plaster be put on large cuts? What is 
said of ointments and salves ? What should be done if there is dirt in 



WOUNDS OF LARGE BLOOD-VESSELS. 159 

If the cut has been made by a sharp instrument but 
has dirt or grit in it, hold its edges apart and wash by 
pouring water on it. Then proceed as above. Do not 
sponge or wipe it. Either cold water or water as hot as 
the hand can bear may be used. Both check bleeding, 
the hot water rather better than the cold. Tepid water 
promotes bleeding. 

A jagged cut, or a wound made by a blunt instrument, 
does not heal as easily as one made by a sharp knife. 
If it is large, or is on a part of the body where it is very 
desirable to avoid a scar, send for a doctor. Meanwhile, 
if blood oozes out fast, check the bleeding by constant 
pressure with sponges wrung out of hot water. 

7. Wo^inds of Large Arteries or Veins need prompt treat- 
ment, lest the sufferer die from loss of blood. If a big 
vein has been divided, the blood will flow out pretty 
steadily and of a dark color. If a large artery has been 
cut, the blood will be brighter red and probably come out 
in spurts. Whichever it may be, the proper thing is to 
send at once for medical aid, and meanwhile to stop the 
bleeding. Do not lose time by trying to decide whether 
the flow is from a vein or an artery, and whether you 
should apply pressure nearer or farther from the heart. 
Many large arteries and veins when cut bleed nearly as 
fast from one end as the other. Press at once on the 
wound as hard as you can, with a handkerchief or any- 
thing of the sort at hand; and, when you have thus part- 
ly checked the bleeding, try pressure all around the cut, 

the wound? If the cut is jagged or apt to be disfiguring? Until 
the doctor arrives ? 

7. Why should wounds of large blood-vessels be treated at once ? 
How does the flow from a vein usually differ from the bleeding of a 
wounded artery ? What had best be done in either case? How pro- 
ceed until skilled advice is obtained ? How may the blood-flow from 



l6o HOW TO CHECK DANGEROUS BLEEDING, 

above and below, and on each side, till you find the 
place where it **does most good." In deep wounds of 
the arms or legs, you will usually find that pressure both 
above and below is necessary. A surgeon would know 
where to apply the pressure in the case of any par- 
ticular wounds, but you do not: your business is to find 
it out by experiment as soon as you can, and not trouble 
yourself with any general rules, which will fail you in 
most particular instances. 

If the wound is on the lower part of a limb and you 
find that you cannot entirely check the loss of blood by 
pressure on it and in its neighborhood, keep up the pres- 
sure and get some one to bind the limb very tightly 
higher up. This is best done as follows: Tie a handker- 
chief loosely round the upper part of the wounded arm 
or leg; then put a stick under it, and twist the stick 
round and round until the handkerchief is so tight as to 
close the arteries, and stop all flow of blood to the lower 
parts of the limb. Such stoppage of the blood-flow for 
half an hour or even a little longer, will do no permanent 
harm, while free bleeding from a wound in a large artery 
or vein may cause death in three or four minutes. 

If a person who has lost much blood begins to breathe 
slowly and irregularly, give him a strong stimulant as 
soon as you can get it, and choose the stimulant you can 
get quickest. If a drugstore is close by, a mixture 
of a teaspoonful of aromatic spirits of ammonia with 
half a tumblerful of water may be given. If brandy or 
whiskey can be obtained sooner, use them. The irregu- 
lar breathing is a sign that the part of the nervous sys- 

a wound in the lower part of the arm or leg be stopped ? If the sufferer 
^hows signs of death from loss of blood, what should be done? What 
is ihe use of the stimulant in this case ? 



ACTIO iV OP ALCOHOL ON BLOOD. l6l 

tern (Chap. XVIII.) which makes the muscles of breathing 
do their work, is ceasing to act, and extra stimulation 
must be given it for a while until the bleeding is 
stanched and blood has again commenced to collect in 
the arteries. 

8. The Action of Alcoholic Drinks on the Circulation. — 
Alcohol in excess, injures the blood, the arteries, and the 
heart. 

Even in moderate doses, it diminishes the power of the 
blood to absorb oxygen, and thus decreases the oxida- 
tions within the body, and lowers its working power and 
its temperature. Large quantities of alcohol cause the 
red blood-corpuscles to become shrunken and distorted, 
and greatly diminish their efficiency as carriers of oxygen 
to all the organs. 

9. The Action of Alcohol on the Plasma. — Continued 
alcoholic indulgence leads to an alteration in the blood- 
plasma, lessening its tendency to form fibrin and to 
clot. Hence even the slight wounds of tipplers are 
apt to result in dangerous bleeding. The fibrin is so 
scanty and the clogging up of the ends of cut blood- 
vessels so slow (p. 138), that all surgical operations on 
such persons are attended with special danger. 

10. The Action of Alcohol on the Arteries. — Alcohol tends 
to make fatty matter collect in the walls of the arteries. 
The oil-drops take the place of the natural tough elastic 
material. Thus the artery is weakened. In consequence, 

8. Action on the blood of even moderate doses of alcohol? How 
does this affect the body ? Action on the red corpuscles of large doses 
of alcohol? 

9. Action on the blood plasma? Why are surgical operations on 
tipplers especially dangerous ? 

10. Action of alcohol on the arteries ? What is an aneurism ? 
Usual result? 



l62 ACTION OF ALCOHOL ON THE HEART. 

the blood, which is forcibly sent into it by the heart, 
stretches its walls and makes it swell out and become 
thin. Such a swelling on an artery is named an aneurism. 
An aneurism usually ends by bursting, and the person 
bleeds to death. 

11. The Action of most Alcoholic Drinks on the Heart is 
to excite it and hurry its beat. Whether pure alcohol, 
diluted with water, has this action, is not certain. It is 
certain that most ordinary alcoholic drinks, as wines and 
spirits, have it. When the beating of the heart is quick- 
ened, each contraction of its muscles takes about as long 
as when it beats slower, but the time of repose between 
the beats is shortened. The result is that the heart is 
overworked. It has not sufficient rest for its proper 
nourishment, and gradually undergoes a change known 
diS> fatty degefieration. Fatty or oily matter takes the place 
of the proper muscle-substance, and the heart, becoming 
more and more weakened, at last cannot pump the blood 
over the body. The consequence, of course, is death. 
Fatty degeneration of the heart is so often due to indul- 
gence in alcoholic stimulants, that a fatty heart is often 
called by physicians a ^^whiskey-heart.' 

II. What is the action on the heart of all ordinary alcoholic drinks ? 
How is the resting time of the heart affected when its beat is quick- 
ened? Result? What is fatty degeneration? Consequence w^hen 
it occurs in the heart ? 



CHAPTER XV. 

RESPIRATION OR BREATHING. 

1. The Use of Respiration is to renew the air in the 
lungs. This is necessary because the blood, as it flows 
through the lungs, is all the time taking something 
from the air within them, and giving something to it. 
If this air were not passed out, and fresh air taken in its 
stead, it would soon have nothing left of what the blood 
wants. It would also become so loaded with the waste 
matter the blood gives off to it, that it could take no 
more of it, and so the blood would not be purified. 
Suffocation is death from want of fresh air in the lungs. 

2. What the Blood Takes from the Air.— Blood gets 
nourishment for the body from the alimentary canal. 
But we have learned (Chap. VIII.) that in order that 
foods may give us power and keep us warm, they must 
be oxidized, and, clearly, they cannot be oxidized unless 
oxygen is supplied. The blood, into which the digested 
foods are taken, as it flows through the lungs absorbs 
this necessary oxygen. 

3. What the Blood Gives to the Air.— The blood in its 
passage through the lungs gives off to the air, heat, 

1. What is the use of respiration ? Why is it necessary? What is 
suffocation ? 

2. Where does blood get nourishment for the body? Why is 
oxygen necessary as well as food ? Where does the blood get 
oxygen ? 

3. What does blood give to the air as it passes through the lungs ? 



164 CAkBONlC ACID, 

water, a gas named carbonic acid, and a small quantity of 
organic matters. 

The heat is easily recognized : you know that your 
breath is warm. The water usually comes out in the 
form of invisible vapor. On a cold day, however, it is 
seen as mist, streaming from the nostrils ; and any day 
it can be made visible by breathing on a cold bright 
object, as a mirror or knife-blade. 

The carbonic-acid gas and the organic matters given 
out in the breath, are unfortunately not so easily made 
apparent as the heat and the water-vapor. They are, 
however, of much more importance. Carbonic acid is 
one of the chief waste substances made by the body 
and must be removed from it. The organic matters 
poison the body, if air containing them be breathed 
over and over again. 

4. How Carbonic Acid is made from Charcoal. — You 
remember that when a human body is incompletely 
burned (Chap. I.) it forms a black mass of charcoal. 
Now charcoal is a mixture of a substance named carbon 
with some minerals. We may call it impure carbon. 
When it is burned, its carbon combines with oxygen and 
makes carbonic-acid gas. Just as rust is oxidized iron, 
so carbonic acid is oxidized carbon ; though it is a gas, 
instead of being solid like iron-rust. 

5. How Carbonic Acid is made in our Bodies. — All our 
organs contain animal matter (p. 10), and all animal 

How may the heat be recognized ? How the water ? Name a chief 
waste matter produced by the body. What is the result of frequently 
breathing air containing organic matters given out in the breath ? 

4. What is left when a human body is incompletely burned ? What 
is charcoal ? What may we call it ? What happens when it is 
burned? How does carbonic acid resemble and differ from iron-rust? 

5. What do all our organs contain? What do all animal matters 



FORMATION OF CARBONIC ACID IN THE BODY, 1 65 

matters leave charcoal when they are partly burned. 
They must, therefore, contain carbon. It seems odd 
that this should be so, and yet that they should not be 
black ; but carbon is not always black. A diamond is 
nearly pure carbon ; and can, by being heated, be changed 
into ordinary black carbon, and then burnt and com- 
bined with oxygen to make carbonic acid. Very few 
substances which contain carbon combined with other 
things, are black ; as, for example, carbonic-acid gas 
itself, which is quite colorless. In our organs, the carbon 
is all combined with other things; it only shows its black 
color when the heat of the fire has separated them from it. 

As long as we live, our bodies are slowly burning or 
oxidizing (Chap. VIII.). By this burning, carbonic acid 
is produced from the carbon of their organs. When we 
work hard, a great deal is made, and when we are at rest 
much less. But even in deep sleep, oxidation is going 
on inside our bodies all the time, to supply animal heat, 
and force or power for every heart-beat, and each move- 
ment of breathing. The carbonic acid produced by 
oxidation in the body, must be removed. When it is 
abundant, the organs cannot receive or use the oxygen 
which they need in order to do their work. 

6. Breathing Air which contains much Carbonic Acid, 
will not Support Life. — The more carbonic acid in the 
air, the less oxygen. If there is very much carbonic 

leave when they are partly burned ? What must they, then, contain ? 
Illustrate the fact that things containing carbon are not always black. 
In what state does carbon exist in our bodies ? When does it show 
its black color? What occurs as long as we live? What is produced 
by the burning? Why is oxidation necessary even during deep 
sleep? Why must the carbonic acid produced in the body be re- 
moved ? 

6. How does the presence of carbonic acid in air affect the quan- 
tity of oxygen ? What is the consequence to life if there is much of 



1 66 FUNCTION OF THE LUNGS. 

acid, there is not enough oxygen to supply the needs of 
the body and maintain life. Death in such case results 
from suffocation, which may be more plainly named 
oxygen-starvation. The ^'foul air" which is sometimes 
present at the bottom of deep wells or pits, and kills 
people who incautiously go down them, does so be- 
cause it contains much carbonic acid. Carbonic acid is 
not itself very poisonous, but air containing much of it 
is fatal, because carbonic acid has taken the place of 
the necessary oxygen ; and air without plenty of oxy- 
gen will not support life. 

7. Excretion. — The process of removing its wastes 
from the body, or getting rid of things which have 
done their work in it and are no longer wanted, is 
named excretion. The waste substances themselves are 
also called excretions. Organs which remove them are 
excretory organs. 

8. The Lungs Perform a Double Duty. — So far as oxygen 
is concerned, they are organs for taking something use- 
ful into the body, and are receptive organs. So far as 
carbonic acid is concerned, they are excretory organs. 

9. How the Air is Purified. — Every living human being 
and every one of the lower animals is all the time taking 
oxygen from the air and giving carbonic acid to it. So 
is every fire and every burning candle. We may natu- 
tally ask, How is the air kept fit to breathe ? 

it? Give another name for suffocation? Why may carbonic acid be 
called a ** negative poison"? 

7. What is the process of excretion ? What substances are named 
excretions ? What are excretory organs ? 

8. What are the two main duties of the lungs? 

9. How do living animals and fires alter the air ? What living 
things purify the air ? Name a chief food of green plants. What 4o 
they do with the carbonic acid they take from the air? How do 
animals and plants help one another ? 



RESPIRATORY ORGANS, 1 67 

The air is purified by plants. All green plants, when 
in the light, take up carbonic acid from the air. It is 
one of their chief foods. From the carbonic acid, they 
pick out the carbon and use it in making starch and 
sugar and oils, and other things. The oxygen, they give 
back to the air. Thus plants not only make food for 
animals but keep the air fit for them to breathe; while 
animals by their breathing supply food for plants. 

10. The Air inside the Lungs must be Frequently 
Changed. — If tlie air inside the lungs be not frequently 
replaced by fresh air, it becomes so full of carbonic acid 
that it can take no more from the blood; and so poor in 
oxygen that it cannot supply the blood with enough of 
that gas. Dark-colored venous blood comes to the lungs 
by the pulmonary artery (Chap. XIII. ), containing little 
oxygen and much carbonic acid. Through the thin walls 
of the pulmonary capillaries, it gives carbonic acid to, 
and takes oxygen from, the air inside the lungs, and 
thus, replenished and purified, is returned to the left side 
of the heart to be distributed over the body. 

11. The Respiratory Organs are — (i) the lungs, in which 
the blood is exposed to the action of the air ; (2) the 
air-passages, through which air enters and leaves the 
lungs; (3) certain muscles {muscles of respiration), and 
the skeleton of the thorax, which work together to al- 
ternately expand and contract the chest, and thus renew 
the air inside the lungs. 

10. What happens if the air within the lungs is not frequently re- 
newed ? What sort of blood does the pulmonary artery bring to the 
lungs? What does this blood do as it flows through the pulmonary 
capillaries ? What becomes of it after leaving the lungs ? 

11. Name the respiratory organs. Use of the lungs? Of the air- 
passages ? Of the respiratory muscles and the skeleton of the 
chest? 



1 68 



VOICE, 



12. The Air- Passages are the nostril-chambers, the phar- 
ynx, the larynx, the windpipe 
or trachea, the bronchi, and 
the bronchial tubes. The nos- 
trils (Fig. 42) open behind, 
into the upper part of the 

r Wll^^^^j^^yH^ ^^ pharynx. From the front of 
"^ " ^ ^^^^ ^j^^ pharynx, below the level 
of the root of the tongue, 
k, and above the opening into 
the gullet, the larytix pro- 
ceeds. Its opening is over- 
hung by a sort of lid, e, 
named the epiglottis. This lid 
shuts down when food or 
drink is passing through the 
pharynx, but stands up at 
other times. 

13. The Larynx is the or- 
gan in which voice is pro- 

FiG. 42.— The mouth, nose, and duccd. The hard projection 

pharynx, with the commencement of 

the gullet and larynx, as exposed by in front of the Ueck, COm- 

a section, a little to the left of the mid- ' 

dieof the head. ^ vertebral column; monly named '' Adam's ap- 

b. erullet! c. windoioe: e. eois^lottis: ^ ^ 




y;,soft palate;^, opening^of Eusta- pj^^- j^ causcd by the larynx, 



gullet; <r, windpipe; ^, epiglottis; 

soft palate; g, opei ' - " 

chian tube; k, tongue; 

w, the sphenoid bone on the base of „,u:^U \r^ ^ ^^^4-: l^^:^^,,r. K^^r 
the skull; n, the fore part of the skull- whlch IS a CartllaglUOUS bOX 
cavity; o^p^q. the turbinate bones of / 7 tt*. \ t j u 

the outer side of the left nostril-Cham- \a, Jh Ig. 42 j lined by mu- 

cous membrane. At one 
place the mucous membrane is pushed in from each side, 
so that only a narrow slit is left in the middle. This 

12. Name the air-passages ? Into what do the nostrils open be- 
hind ? Where does the larynx begin? What is the epiglottis? Its use? 

13. Name the organ of voice ? What is the larynx ? What is the 
'glottis ? What are the vocal cords ? 



THE GLOTTIS. 



169 



slit (^, Fig. 43) is named the glottis. The folds forming 
its sides are elastic and tightly stretched ; they are 
named the vocal cords. 




Fig. 43. — The interior of the larynx as seen when viewed from above and behind, 
through Its opening into the pharynx, i, hyoid bone, which in Hfe has the root of 
the tongue attached to it ; 5, lower part of the pharynx cut open ; 6, top of the 
gullet; 8, 9, 10, the right edge of the opening of the larynx; a, a\ a", epiglottis; 
c, glottis (the dotted lines leading from the letter point to the edges of the vocal 
cords); b' ^ b\ hollows in the mucous membrane of the larynx, above the vocal 
cords ; l\ 3, rounded prominences of the mucous membrane, named the false 
vocal cords : they play no direct part in the production of voice. 



14. How Voice is Produced. — Certain muscles separate 
the vocal cords and widen the glottis ; others bring the 

14. How do muscles alter the glottis ? What is its state in quiet 



170 



TRACHEA AND BRONCHIAL TUBES, 



cords together and narrow the glottis. In ordinary quiet 
breathing the glottis is wide open, and air passes through 
it without causing sound. When it is narrowed, and air 
driven through it from the lungs, voice is produced. 
The sounds produced in the larynx are afterwards 

altered, and added to, in various 
ways in the throat, mouth, and 
nose. Thus voice is altered or 
improved into speech. 

15. The Windpipe or Trachea 
(^, Fig. 44) is a stiff tube which 
may be easily felt in the lower 
part of the front of the neck of 
thin persons. In its walls are 
horseshoe - shaped cartilages, 
which keep it open. The wind- 
pipe enters the thoracic cavity, 
and there divides into two bron- 
chi^ ov\^ for each lung (^, Fig. 

44). 

16. The Bronchial Tubes.— 

soon as it 




trachea, 



Fig. 44. — The larynx, 
bronchi, and bronchial tubes, seen 
from the front. The right lung 

(to the left in the figure) has Each brOUChuS 
been dissected away to expose the 



as 



bronchial tubes a larynx; /, eutcrs the luno;, bcofins to divide, 

windpipe; d^ right bronchus: its ^^ o » 

branches are bronchial tubes. ^^^^ ^„^ ^^^^ again, like the 

trunk of a tree. The branches are hollow, and the end 
ones are very small indeed. They are all named bronchial 
tubes. On the left side of Fig. 44 the right lung has been 
cut away, so as to show the bronchial tubes. 



breathing? How is voice produced? How is voice converted into 
speech ? 

15. What is the windpipe? How is it kept open? Where and 
how does it end? 

16. What is said concerning the bronchial tubes ? 




THE LUNGS, 1 71 

17. The Lungs lie inside the thorax, one on each side 
of the heart (Fig. 2). They are elastic spongy masses, 
full of tiny cavities, named air-cells. Into the air-cells 
the smallest bronchial tubes open (Fig. 45). Thus air 
gets to them, ready to give b 
oxygen to the blood, and carry 
oif carbonic acid from it. 

18. Inspiration and Expira- 
tion. — Breathing consists of 
breathing-in and breathing- 
out, turn and turn about. 
Breathing-out gets rid of air ^,^^- 45 -A small bronchial tube, 

& c5 a\ b^ <r, air-cells connected with it. 

which has become foul in the Magnified about twenty times. 

lungs: it is named expiration. Breathing-in conveys new 
air to the lungs in place of that which has been expired: 
it is known as inspiration, 

19. The Movements of the Chest alternately enlarge 
and diminish its cavity. When it is enlarged, air enters 
it ; when it is diminished, air is driven out. We may 
compare the chest in this respect to a pair of bellows. 
The chief difference is that air enters the bellows through 
one aperture, and is driven out through another ; while 
in breathing, air comes and goes by the same road, the 
windpipe, which answers to the nozzle of the bellows. 

20. How the Chest- Cavity is Enlarged to cause Inspira- 
tion. — The enlargement of the chest is brought about 



17. Position of the lungs? Structure? How does air reach the 
air-cells of the lungs ? 

18. Of what does breathing consist? Use of breathing-out? Its 
technical name ? Of breathing-in ? Its technical name ? 

19. Result of the chest - movements ? What happens when the 
chest is enlarged? Diminished? Illustrate. What part of the re- 
spiratory organs corresponds to the nozzle of a pair of bellows ? 

20. How is the chest enlarged ? Position of the ribs in expiration ? 



172 



INSPIRA TION. 



by certain muscles which move the ribs, and by the 
diaphragm. 

The ribs during expiration slope downwards, the end 
of each attached to the spinal column being higher than 
the end attached to the breast-bone (Fig. 5). When we 
draw a breath, certain muscles pull up the front ends 
of the ribs. When this occurs, the breast-bone is pushed 
[artlier away from the back-bone, and the depth of the 
chest between breast-bone and spinal column is in- 
creased. 

That raising the front end of the ribs must push the 
breast-bone forwards may be readily understood by ex- 
amining Fig. 46. In the figure, ab represents the spinal 
column, and st the breast-bone. 
The position of the ribs in expira- 
tion is indicated by the rods c and 
d\ their position in inspiration, 
by the dotted lines c' and d' . It is 
clear that when the ribs are raised 
the sternum must be separated 
farther from the back-bone. 

21. Action of the Diaphragm dur- 
ing Inspiration. — The diaphragm 
(^, Fig. i) is a dome-shaped muscle, 
with its hollow side turned to- 
wards the abdomen. When it 
contracts, it flattens, and thus in- 
creases the chest-cavity. At the same time, it pushes 
down the liver, stomach, and intestines. These make 

In inspiration ? What is the result of raising the front ends of the 
ribs? 

21. Form of the diaphragm ? How altered when it contracts ? Re- 
sult as regards the chest? The abdomen ? 




Fig. 46. — Diagram of a 
model to illustrate how the 
chest-cavity is increased from 
before back when the front 
ends of the ribs are raised, ab 
represents the spinal column; 
st^ the breast- bone; <:, d^ the 
ribs in expiration; c\ d\ the 
ribs in inspiration. 



lE^tPIRA TidN, 



i/^3 



foorh for therriselves by pushing out the soft front wall 
of the abdomen, which therefore protrudes; 

22. The Combined Action of the Diaphragm and of the 
Muscles which Raise the Ribs is such as to considerably 
increase the chest-cavity. This is illustrated in Fig. 47. 
In B are shown the size and form of the thoracic 
cavity, and the position of the diaphragm, after an expi- 




FiG. 47. — Diagrams showing the form and size of the chest and abdomen during 
inspiration, -4, and expiration, B. C, chest-cavity; Z>, diaphragm; E^ spinal col- 
umn; F^ collar-bone; St^ sternum; Ab^ abdomen; (?, hip-bone; Zf, coccyx. 

ration. A represents the chest and diaphragm at the 
end of an inspiration. 

23. Expiration. — In expiration, the chest-cavity is di- 
minished, and air driven out of the lungs. It is ordina- 
rily brought about without muscular work. The mus- 

22. What is the result of the combined action of the diaphragm and 
the muscles raising the ribs during inspiration ? 

23. What happens during expiration? How is it ordinarily brought 
about ? Explain ? 



l)'4 SNEEZING AND CdUGHING. 

cles which have pulled up the ribs and sternum (to dause 
inspiration) relax, and these bones fall back into their 
former places. The diaphragm also relaxes, and the 
liver, stomach, and intestines, pressing against its under- 
side, then push it up towards the chest. Thus the lungs 
are squeezed and air driven out of them. 

24. Sneezing and Coughing. — The mucous membrane 
lining the nose, and the larynx is very sensitive. Any- 
thing irritating it causes a peculiar kind of violent ex- 
piration, calculated to drive a powerful blast of air 
through the air-passages and force away the irritant. 
When the inside of the nose is tickled, a sneeze follows. 
The irritation makes us first draw a deep breath, with- 
out our willing it at all, and in spite of our will if we try 
to prevent it. Then, when the lungs are filled with air, 
the glottis (p. 169) is closed and the chest compressed. 
Next, the glottis is suddenly opened and the compressed 
air rushes out of the lungs. It is made to go through 
the nose, because the root of the tongue and the soft 
palate are brought together, so as to close the opening 
from the pharynx to the mouth. Sneezing is a good 
example of the resemblance of our bodies in many ways 
to machines, made to do a certain thing under certain cir- 
cumstances. The control which we have over them by 
our will is not at all complete. We can neither prevent 
a sneeze when the nose is irritated, nor make even a 
good imitation of a real sneeze when it is not. 

A cough differs from a sneeze, mainly in the fact that 
the air is allowed to pass out through the mouth. Its 
use is to drive out anything irritating the larynx. 

24. What results when the mucous membrane of nose or larynx is 
irritated ? Describe the process of sneezing ? What may we learn 
from it ? Of coughing ? Its use ? 



APPENDIX TO CHAPTER XV. I/J 



APPENDIX TO CHAPTER XV. 

1. A sheep's lungs with the windpipe attached may be readily ob- 
tained from a butcher. It is best to secure them and the heart all 
together, as unless the heart be carefully removed holes are apt to 
be cut in the lungs. 

2. Examine the windpipe, and trace it down to its division into the 
bronchi. In the wall of the windpipe note the horseshoe-shaped 
cartilages which keep it open, and which are so arranged that the 
dorsal aspect of the tube (which lies against the gullet) has no hard 
parts in it. 

3. Trace the main right bronchus to its lung, and then, cutting 
away the lung-tissues, follow the branching bronchial tubes through 
the organ. Note the cartilages in their walls. In the sheep there is 
a small extra bronchus on the right side, which goes to the upper 
part of the right lung. It is not present in man. 

4. Carefully divide the left bronchus w^here it joins the windpipe, 
and lay it and its lung aside. Then slit open the trachea, the bronchi 
still attached to it, and the bronchial tubes. Observe the soft pale red 
mucous membrane lining them. 

5. In the left bronchus, which has still an uninjured lung attached 
to it, tie air-tight a few inches of glass tubing of convenient size. 
On the end of the glass tube then slip a few inches of rubber tubing. 
On blowing through the rubber tube the lung will be distended, and 
as soon as the opening is left free it will collapse; in this way its 
great extensibility and elasticity will be seen. 

6. Blow up the lung moderately, and while it is distended tie a 
string very tightly around the bit of rubber tubing. This will keep 
the air from escaping; the distended lung can now be examined at 
leisure, and its form, lobes, and the smooth moist pleura covering it 
be better seen than when it is collapsed. 

7. The diaphragm may be readily seen in the body of any small 
animal (rat, kitten, puppy), on removing the abdominal viscera. The 
liver and stomach must be cut away with especial care. 

a. When the above viscera are removed, the vaulted diaphragm will 
be seen, and through it the pink lungs. 

b. Pull the diaphragm down, imitating its contraction and flattening 
in inspiration. The lungs will be seen to follow it closely, expanding 
to fill the space left by it in its descent. 

c. Make a free opening into one side of the thorax. The corre- 
sponding lung will collapse, and be no longer influenced by move- 
ments of the diaphragm. 

d. Now open the other side of the chest: its lung also shrinks up; 
the structure of the diaphragm (its tendinous centre and muscular 
sides) can now be better seen, as also the attachment of the pericar- 
dium to its thoracic side. 



' CHAPTER XVI. 

HYGIENE OF RESPIRATION. 

1. Introductory. — We all know, of course, that air which 
is not fresh is unpleasant to breathe, but many persons 
appear not to know that it is also poisonous. 

Suppose you put an air-tight bag, containing two or 
three pints of air, close to your mouth, and kept your 
nostrils closed, so that no air could enter the lungs but 
that in the bag. For the first few breaths you would 
have no trouble. But after you had breathed in and out 
of the bag several times the air within it would not have 
enough oxygen left to supply the needs of the body, and 
would be so full of excretions as to be poisonous. 

If you want to keep a pet puppy or kitten in a box, 
you make an air-hole. When asked why, you reply that 
the animal would die without air, yet there is already in 
the box as great a quantity of air as could get in if there 
were dozens of holes. What you want is to give your 
pet fresh air from the outside so that it will not have to 
breathe over and over again that which becomes more 
poisoned every time the animal draws it into his lungs. 
When we shut ourselves up in rooms with tight win- 

I. What is said of air that is not fresh? How is air altered every 
time it is breathed ? What would happen if you tried to go on breath- 
ing the air shut up in a small bag ? What is the real reason that an 
an'mal shut up in a box needs an air-hole? Apply to closed rooms. 



STARVATION AND SUFFOCATION, ifj 

dowS and no open fireplaces, we are as badly off as the 
puppy would be in his box, without an air-hole, if you 
should occasionally open and shut the lid quickly, as 
we do our doors on a cold day. 

2. Starvation and Suffocation Compared. — If a man gets 
no food, he soon dies of starvation. If he gets some food, 
but not enough for the needs of his body, he lives longer, 
but his whole body is weak. At last he dies of slow 
starvation, unless some disease attacks his feeble organs, 
and kills him before want of nourishment has had time 
to do so. 

It is much the same as regards the supply of oxygen 
in the air we breathe. If there is no oxygen in it, death 
takes place in a few minutes. Death from suffocation 
occurs quicker than death from starvation, because our 
bodies have laid up in them but very little more oxygen 
than they need at the moment; whereas, in fat and some 
other tissues, there is a store of nourishing matter which 
the body can make use of when its food is not enough. 
Fat, when not present in such excess as to hamper 
various organs in their work, may be compared to a 
little money laid by in a savings-bank, and ready for use 
in case the regular supply gives out. There is no such 
bank in our bodies where extra oxygen can be stored. 
In health, the blood and each organ possess just a little 
more than they want at the moment, but that is all. It 
is like a few cents of pocket-money, which does not last 
long if we have to live on it. 

2. What happens if a man does not get enough food ? Of what 
does he die ? If he gets no oxygen ? Why does a man die of suffo- 
cation sooner than of starvation? To what may fat be compared? 
How much oxygen do the blood and organs possess in health ? To 
what compared? 



178 RESULTS OP BREATHING FOUL ALR, 

3. Foul Air is Worse than Insufficient Food. — If a man 

be nearly starved to death and then be carefully nour- 
ished, he may soon be all right again, but if he has been 
slowly poisoned, as well as starved, he is not so likely to 
recover. When a man does not get enough fresh air to 
breathe, he is not only starved for want of oxygen, but 
poisoned. The wastes or excretions of the foul air are 
absorbed into the blood from the lungs, and are then 
carried by the blood to every organ. The health of the 
body, when pure air is breathed, depends on the perfec- 
tion with which the blood carries oxygen to every nook 
and corner. When impure air is breathed, the hurtful 
substances taken into the blood as it flows through 
the lungs, are carried in exactly the same way to all 
parts. 

You know that there are quick poisons and slow 
poisons. Quick poisons kill in a few minutes or a few 
hours. Slow poisons may not kill for weeks, months, 
or even years. Many slow poisons do not themselves 
actually cause death, but they so much weaken some of 
the organs that the body is very apt to take disease, and 
in its feeble condition cannot master and overcome it. 
Foul air is rarely foul enough to act as a quick poison, 
but unless proper care be taken, the air in rooms much 
lived in, soon becomes foul enough to act as a slow 
poison. How quick or how slow, depends simply on how 
foul the air may be. 

3. What is the usual result if a man be carefully fed after being 
nearly starved to death ? If he has been also poisoned ? Apply to 
want of sufficient fresh air. How are the poisonous matters in foul 
air carried over the body ? 

What are quick poisons ? Slow ? How do many slow poisons act ? 
What is said of foul air as a quick and a slow poison ? 



DEATH FROM WANT OF FRESH AlR. Ijg 

4. Rapid Death from Insufficient Supply of Fresh Air. — 

Cases of quick poisoning from repeated breathing of the 

same air are not frequent. Fortunately, few doors and 

windows fit so tight as t6 prevent fresh air from getting 

into a room, and foul air out of it, fast enough to keep one 

or two people alive. The very deadly result of breathing 

the same air repeatedly has, however, been terribly 

proved in more than one instance. The steamship 

" Londonderry," a few years ago, sailed from Liverpool 

with two hundred passengers on board. Stormy weather 

coming on, the captain ordered all the passengers into a 

small cabin and then closed its openings. ^' The wretched 

passengers were now condemned to breathe over and 

over again the same air. This soon became intolerable. 

There occurred a horrible scene of frenzy and violence, 

amid the groans of the dying and the curses of the more 

robust. This was stopped by one of the men contriving 

to force his way on deck, and to alarm the mate, who 

was called to a fearful spectacle. Seventy-two were 

already dead and many were dying ; their bodies were 

convulsed, the blood starting from their eyes, nostrils, 

and ears." All this occurred within six hours. 

Not merely some fresh air, but a certain quantity of 

fresh air is necessary to maintain life. It seems almost 

absurd to point out this fact, yet many folks act as if they 

believed that any air-hole, with little regard to its size, 

were sufficient. The greater the number of people in a 

room, the more abundant must the air-supply be. 

Ignorance of this fact led to the horrible catastrophe of 

4. Why is quick poisoning from foul air not frequent ? Give an ac- 
<:ount of the example of it on board the " Londonderry." What be- 
sides " some" fresh air is needful ? When must the fresh air be more 
^abundant? Describe the catastrophe of the ** black hole of Calcutta.' 



1 80 VEN TILA TION. 

the '' black hole of Calcutta." One hundred and forty- 
six prisoners were shut up in a small room with two 
narrow open windows. These windows would probably 
have supplied abundant fresh air for ten or twenty per- 
sons, but they were so insufficient for the needs of the 
large number locked up in the room, that, in eight 
liours, one hundred and twenty-three died. 

5« Ventilation. — Most of us have to spend a large part 
of our time within more or less closed rooms. In order 
that the air in them may continue fit to breathe, it must 
be changed all the time. This removal of the foul air 
and its replacement by fresh, is known as ventilation. 
Ventilation is "sufficient" when it renews the air fast 
enough. It is ^^^^ when, in addition to being sufficient, 
it does not cool a room too much or cause injurious 
draughts. 

6. The Amount of Ventilation Necessary depends of 
course on many things. If there are two people living 
in a room, they will require just twice as much fresh air 
as one; and fifty will need fifty times as much. School- 
rooms, churches, theatres, and other like places, where 
many people collect, need very free ventilation. All 
such burning things as fires or candles or gas or oil- 
lamps, take valuable oxygen from the air and give 
hurtful carbonic acid to it. In ventilating a room, allow- 
ance must therefore be made for them. Ventilation just 



5. What is necessary that the air in inhabited rooms may continue 
fit to breathe ? What is ventilation ? Sufficient ventilation ? Good 
ventilation ? 

6. How does the number of persons in a room affect the amount of 
ventilation necessary ? Examples of rooms which especially need 
free ventilation? How do burning things alter the air? Why is 
more ventilation necessary when the gas is lighted ? 



CONSEQUENCES OF DEFICIENT VENTILATION. l8l 

sufficient in the morning, will not be enough at night 
wlien the gas is lighted. 

7. How Deficient Ventilation may be Recognized. — The 
nose generally affords the most sensitive as well as the 
most convenient test of the sufficiency of the ventilation 
of an inhabited room. If ill ventilated, the air will 
usually smell " close." Those who have been in the 
room for some time are not likely to realize how fgul the 
air has become, as the nose gradually gets used to air 
around it, which would be extremely unpleasant to one 
just entering the room. If the room smells even the 
least bit '^ close" to a person entering it from out of 
doors, it needs more ventilation. 

8. Consequences of Living in Insufiiciently Ventilated 
Booms. — A stay of an hour or two in a room not supplied 
with enough fresh air, results in headache, dulness, and 
sleepiness, which soon go off when we get out again 
into the fresh air. Children have often been punished 
for seeming neglect of their studies, when the foul air of 
the school-room was really to blame. 

If one spends a considerable portion of every day in a 
badly ventilated room, the whole body is enfeebled. The 
blood becomes poor in red corpuscles, and the face pale; 
appetite is lessened, digestion imperfect, and the muscles 
weak. The body, not getting enough oxygen and being 
at the same time slowly poisoned by breathing its own 
wastes over and over, has but little reserve force. It is 



7. How does the air of an ill-ventilated room affect the nose ? 
Why may foul air not be perceived by those who have been some 
time in an insufficiently ventilated room ? When does a room need 
more ventilation ? 

8. What are the consequences of staying for an hour or two in a 
badly ventilated room ? What of spending several hours daily \x\ 



1 82 EFFECTS OF TIGHT LACING. 

liable to take disease, and when disease occurs, there is 
less chance of recovery. 

Consumption and other lung-diseases are especially- 
frequent in persons who live in badly ventilated rooms. 
So are colds of all kinds. 

9. Pree Chest-Movements are Necessary for Healthy 
Breathing. — Plenty of fresh air to breathe is not of much 
use if^ the chest is so imprisoned that it cannot expand 
properly. No garment which checks the free movements 
of thorax and abdomen in breathing, should be worn. 
The tight lacing which used to be thought elegant, and 
is still indulged in by some who think a distorted form 
beautiful, does harm in many ways. In the first place it 
makes all healthy exercise impossible. A tightly laced 
person gets ^' out of breath " on the least exertion. 
Many a woman complains that she is unable to attend to 
her household duties, because the least exertion fatigues 
her, when all that is the matter is that she has so laced 
her chest that it cannot do its breathing work properly. 
Tight lacing also hampers the abdominal organs. It so 
narrows the chest (Fig. 12) that lungs and heart are 
pushed down towards the abdomen, to get room. The 
heart is driven so close against the stomach that even a 
moderate meal is apt to press unnaturally against it 
(p. 127), and so its working is interfered with. The 
livers of those who have practised tight lacing are often 
found to have hard unhealthy cords on them, caused by 
pressure from the lower ribs, squeezed in by the corset. 

badly ventilated rooms? What diseases are especially frequent in 
those who live in ill-ventilated rooms? 

9. What is necessary for healthy breathing, besides pure air ? How 
does tight lacing do harm as regards exercise and work ? As regards 
the heart? As regards the liver? 



EXPANSION OF CHEST BY EXERCISE. 



183 



10. Expansion of the Chest by Exercise. — Some persons 
are born with narrow chests, and are predisposed to lung- 
diseases. Proper exercise, regularly performed, will do 
a great deal to widen the chest. Rowing is good for 





Fig. 48. 



Fig. 49. 



Fig. 48. — Part of the celebrated statue known as the " Venus of Milo," a recog- 
nized standard of female beauty. 

Fig. 49. — The dressmaker's idea of a beautiful waist. 

this purpose, but certain gymnastic exercises are better. 
They often increase the size of the thorax even in a few 
weeks. A delicate person should get skilled advice as to 
the kind and amount of work to do in a gymnasium. 
Otherwise he may easily do himself harm. 



10. How may the chest be made larger? What should a delicate 
person do before beginning work in a gymnasium ? Why ? 



l84 ACTION OF ALCOHOL ON RESPIRATORY ORGANS. 

11. Mouth-Breathing. — Quite a number of people 
breathe through the mouth instead of the nose. This 
not only gives the face a weak silly look, but it tends to 
cause disease of the lungs and air-passages. 

When air is breathed through the nose, it has to pass 
through a long narrow passage lined with warm moist 
mucous membrane, before it gets into the pharynx. In 
this way it is warmed and moistened before it enters the 
larynx, on its way to the lungs. Air breathed in through 
the mouth is apt to be too cold or too dry when it reaches 
the bronchial tubes, and to injure them and the air-cells 
of the lung. 

The nostrils are very often blocked during a cold in 
the head, but if your nostrils are usually so stopped 
that you find difficulty in breathing through them they 
should be examined by a physician, in order that what- 
ever causes the stoppage may be removed. If a child 
habitually breathes through the mbiith when asleep, it 
is probable that something is wrong with its nose. 

12. Action of Alcoholic Drinks on the Respiratory 
Organs. — Indulgence in alcoholic drinks often keeps the 
mucous membrane lining the air-passages in a congested 
state. It thus increases the tendency to colds of the 
head and chest. There is also a peculiar form of con- 
sumption of the lungs, which is rapidly fatal, and is 
found only in drunkards. 

11. What must air, when breathed through the nose, do before it 
reaches the pharynx ? What results ? Why is air breathed in through 
the mouth likely to injure the lungs ? What should be done if you 
have continual difficulty in breathing through the nose ? 

12. Action of alcohol on the air-passages? Results? What lung- 
dise^se is found specially in drunkards? 



CHAPTER XVII. 
THE KIDNEYS AND THEIR FUNCTION. 

1. Why the Kidneys are Needed. — We have seen how 
the body gets rid of one of its chief waste matters, 
namely, carbonic acid. Another waste substance is 
formed in it every day in large quantity, and if not car- 
ried out would do just as much harm as carbonic acid. 
This waste substance is named urea. It is solid, and so 
cannot be separated by the lungs, which can pass out 
gases and vapors. The urea is removed by the kidneys^ 
along with a great deal of water in which it is dissolved; 
it is thus passed'out in a liquid form. 

Urea contains nitrogen, and is produced when albu- 
mens (p. Z-^ are oxidized, or used up, in doing their 
work in the body. 

2. The Renal Organs include not merely the kidneys, 
but the apparatus by which their secretion is carried to 
the outside of the body and expelled from it. They are: 
(i) the kidneys, two large glands placed in the abdomen; 
(2) the ureters^ or the ducts (p. 6(})^ of the kidneys, which 
carry the secretion to (3) a reservoir, the bladder^ where 
it collects. The bladder is a muscular bag. It contracts 

1. What is urea? Why can it not be separated by the lungs? 
What organs remove it? In what form? What does urea contain? 
How is it produced ? 

2. What do the renal organs include ? Name them. Function of 
ureters? Of bladder? Of urethra? When do the kidneys work? 



1 86 



FIGURE OF RENAL ORGANS. 




Fig. 50. — The renal organs, one-third life size, viewed from behind. ^, lower en(1 
of aorta; Ar^ the right renal artery; R, the right kidney; £/, the right ureter; F«, 
the bladder; Ua^ commencement of urethra; F<r, lower end of inferior vena cava; 
Fir, the right renal vein. 



COMPARISON OF THE EXCRETORY ORGANS, 1 87 

from time to time and expels the liquid which has gath- 
ered in it, through a passage (4) named ih^ urethra. The 
kidneys are at work all the time, separating urea from 
the blood, though the bladder only empties out their 
secretion a few times a day. 

3. The Kidneys lie at the back of the abdominal cavity, 
on the sides of the vertebral column, a short way below 
the diaphragm. Each is about half as big as its owner's 
clenched fist. The blood is sent to the kidneys for purifi- 
cation by two large branches of the aorta, named the 
renal arteries. The kidneys not only take urea from the 
blood, but help in removing other waste matters. 

4. The Chief Excretory Organs Compared as to their 
Functions. — The skin gets rid of a good deal of water, of 
some mineral matters which have done their work, and 
sometimes of a little urea. The duties of the skin as an 
excretory organ are important, and health cannot be 
maintained if they are badly performed. But the chief 
functions of the skin are to protect deeper parts, to 
regulate the temperature of the body (p. 77), and to 
give us the sense or feeling of touch (Chap. XXII.). 

The lungs get rid of much carbonic acid, of small quan- 
tities of very poisonous animal vapors, and of some water. 
They separate no mineral wastes and no urea. The func- 
tion of the lungs as receptive organs, to supply the body 
with oxygen, is as important as their excretory function. 

The kidneys are solely excretory organs. To get rid of 



3. Position of the kidneys ? Size ? How is blood carried to them ? 
What do they do besides taking urea from the blood ? 

4. What is said of the skin as an excretory organ ? Of its other 
functions ? Of the lungs as excretory organs ? Of their other duty ? 
Of the duty of the kidneys ? What do the kidneys remove from the 
bodv? 



1 88 HYGIENE OE THE KIDNEYS. 

waste matters which would poison the body is their only 
duty. Excep)t a very little carried off by the skin, they 
remove all the waste matters containing nitrogen, a 
great deal of water, nearly all the mineral wastes, and 
some carbonic acid. 

5. Hygiene of the Kidneys. — If both kidneys be cut 
out of an animal, it dies in a few hours from blood-poison- 
ing, caused by the wastes which have collected in it. 
Serious kidney-disease amounts to pretty much the same 
thing as cutting out the organs, since they are of little 
use if not healthy. It is always fatal if not checked, and 
often kills in a short time. The things which most fre- 
quently cause kidney-disease are undue exposure to cold, 
and indulgence in alcoholic drinks. 

6. Cold Causes Kidnay-Disease partly by driving blood 
from the surface and congesting the kidneys, partly by 
throwing too much work on them. When the skin does 
not get rid of its proper share of the waste matters of 
the body, it is chiefly the kidneys which have to make up 
for it. 

Nearly all the infectious diseases which are accom- 
panied by a rash on the skin, as measles and scarlet fever, 
also affect the kidneys. During these diseases, the kid- 
neys are more or less inflamed, and in the early stages of 
recovery they are still weak and easily injured. Under 
these circumstances, exposure to cold is very apt to cause 
incurable kidney-disease. 



5. What is the consequence of removing the kidneys? Of kidney- 
disease ? How is serious disease of the kidneys most often produced ? 

6. How does cold injure the kidneys? When have they to do the 
work of the skin ? What diseases especially affect them ? State of the 
kidneys during recovery from these diseases ? Precautions to be 
taken ? 



ACTION OF ALCOHOL ON TL/E KIDNEYS, I89 

7. Alcohol Causes Kidney- Disease in Several Ways. — In 
the first place it overstimulates the organs. Next, when 
its abuse is continued, it interferes with the proper prep- 
aration of the nitrogen wastes: they are then brought 
to the kidneys in an unfit state for removal, and injure 
those organs. Third, when more than a small quantity of 
alcohol is taken, some of it is passed out of the body un- 
changed, through the kidneys, and injures their substance. 

The kidney-disease most commonly produced by alco- 
hol, is one kind of ^^Bright's disease," so called from 
the physician who first described it. The connective 
tissue of the organ grows in excess, and the true excreting 
kidney-substance dwindles away. At last the organ be- 
comes quite unable to do its work, and death results. 

7. State one effect of alcohol on the kidneys. Another? A third? 
What kidney-disease is commonly produced by alcoholic excess ? How 
are the kidneys altered by it ? Results? 



APPENDIX TO CHAPTER XVII. 

To demonstrate the anatomy of the renal organs proceed as follows: 

1. Kill a rat, puppy, or kitten in any merciful way; placing it under 
a bell-jar with a sponge soaked in ether is a good method. 

2. Open the abdomen of the animal, remove its alimentary canal, 
and cut away (with stout scissors) the front of the pelvic girdle. 
The dark red kidneys will then be easily recognized on each side of 
the dorsal part of the abdominal cavity, the right one nearer the head 
than the left. 

3. Dissect away neatly the connective tissue, etc., in front of the 
vertebral column, so as to clean the inferior vena cava and the abdojui- 
nal aorta. Trace out the renal arteries and veins, 

4. Find the ureter, a slender tube passing back from the kidney 
towards the pelvis: it leaves the inner border of the kidney behind 
the vein and artery; and lying, at first, at some distance from the 
middle line, converges towards its fellow as it passes back. 

5. Follow the ureters back until they reach the urinary bladder; 
dissect away the tissues around the latter and note its form, etc. 

6. Open the bladder; find the apertures of entry of the ureters, 
and pass bristles through them into those tubes. Note the mucous 
membrane lining the bladder. * 



i CHAPTER XVIII. 



THE NERVOUS SYSTEM AND ITS FUNCTIONS. 

1. Introductory. — If the inside of your nose be tickled, 
you cannot help sneezing ; it seems so natural to 
sneeze when anything irritates the nostrils that probably 
you never thought about it at all. But if you do think 
about it, you will find that it is something quite curious 
and interesting. If some one puts a soft feather up your 
nose, neither the larynx, nor the lungs, nor the chest- 
muscles, nor the diaphragm, are interfered with; yet 
they all (p. 174) set to work at once to help the nose to 
get rid of what is worrying it, and they do this without 
paying any heed to your will. In other words, they act 
mvoluntarily. They do, apparently of themselves, what 
is likely to help the nose, and they set to work in a very 
orderly way. If any one of them failed to do its share 
of the work, or worked never so little out of its turn, no 
useful sneeze would be produced. 

How the nose obtains such ready and well-planned 
help from all these organs which lie at a distance from 
it, w^e will try in this chapter to explain. 

2. Other Examples of the Help which our Organs give 
to One Another. — Coughing (p. 174) is one that will of 

I. What results from irritating the inside of the nostrils? What 
organs work together to produce a sneeze ? What is meant by say- 
ing that they act " involuntarily " ? What would happen if any one 
of them did not act "just right" ? 



THE MUTUAL HELP OF DIFFERENT ORGANS. I9I 

course come to your nind at once. There are others 
that you may think oi^ as you have also learned that 
when you exercise your muscles, the heart and lungs 
work more vigorously to supply them with sufficient 
nourishment and oxygen, and to carry off their extra 
wastes; that when the air is cold, the blood-vessels of 
the skin contract and drive blood away from the surface 
to prevent too rapid cooling (p. 153); that when your 
body is hot, the sweat-glands become very active so as to 
cool the blood, and through it the internal organs(p. 67); 
that when partly digested food passes from the stomach 
into the small intestine, the gall-bladder at once squeezes 
out bile (p. 116) to be mixed with it, and help the intes- 
tine in digestion and absorption. 

All of the things above mentioned are done without 
our will, and some of them even without our being 
aware when they take place, as the pouring of bile into 
the small intestine. They are but a few examples out 
of hundreds, which show that our organs work together 
for the good of the whole body, and often help one an- 
other without our planning it, or our minds having any- 
thing to do with it. Very clearly there must be some 
means by which the various organs are made to work in 
such harmony. 

3. The Nervous System. — When we try to imagine how 
each organ might be put in communication with all the 
others, probably the first idea that comes to mind is that 

2. Of what is coughing an example ? How do the heart and lungs 
help the muscles during exercise ? How do the blood-vessels of the 
skin keep the rest of the body from being too much cooled ? How do 
the sweat-glands aid the rest of the body ? How does the gall-bladder 
aid the small intestine in digesting? In what way are the above ac- 
tions performed ? What do these few examples show ? 

3. In thinking of communication between the organs, what idea 



192 DIAGRAM OF THE NERVOUS SYSTEM. 




Fig. sff.— Diagram illustrating: the general arrangfement of the nervous system. 



THE CHIEF NERVE-CENTRES, 193 

there might be some sort of telegraph-system in the 
body. If there were something like telegraph-wires 
running from all the organs to a central office or ex- 
change, then word of the state and needs of any organ 
might be sent from it to the central office, and proper 
messages be sent out from the central office to those 
other organs whose help was wanted. This is in fact 
something very like what does take place. 

If the dead body be dissected, a great many white 
cords are found which run all through it, and go into 
the skin, and the mucous membranes, and the heart, and 
the lungs, and each muscle, and so forth. These cords are 
nerves. If one be followed back from where it enters any 
of the above parts, it will be found at last tq join a 
much larger mass to wliich other nerves are also united. 
This mass is a fiej've- centre. The nerves and nerve- 
centres together make the nervous system. The nerves 
answer to the telegraph-wires, and the centres to the 
main offices from w^hich the wires spread over the 
country. 

4, The Chief Nerve-Centres are the brain, the spinal 
cord, the sympathetic ganglia. You have already learned 
that the brain lies inside the skull (p. 19), and the spinal 
cord runs down inside the back-bone. At the under 
part of the skull, where it fits on the back-bone, is a 
large hole, through which the brain and spinal cord 
unite. Strictly speaking, therefore, the brain and spinal 
cord make only one centre; they are often spoken of 

might occur to us ? What really does take place ? What are nerves ? 
What is found when a nerve is traced back from a muscle or the skin ? 
Name of the mass? Of what does the nervous system consist? To 
what are nerves and nerve-centres compared ? 

4. What are the chief nerve-centres ? Where does each He ? How 
do they join ? What is the cerebrospinal centre ? 



194 



THE BRAIN, 



together as the cerebrospinal ce7itre. The sympathetic 
ganglia will be described farther on. 

5. The Brain of an adult usually weighs about three 
pounds. 

It has two chief parts (Fig. 52), the great brain or cere- 
bruM^ A, and the small brain or cerebellum^ B, It is joined 
to the spinal cord by the 7nedulla oblongata^ D, The parts 




Fig. 52,— Diagram illustrating the general relationships of the parts of the brain 
as seen from the side. A^ cerebrum ; B, cerebellum ; Z>, medulla oblongata. 

of the brain are not really so widely separated as is rep- 
resented, for the sake of clearness, in Fig. 52. They lie 
closely packed together, as shown in Fig. 53. 

The cerebrum fills all the front and upper part of the 
skull-cavity. It is much larger than the cerebellum, and 



5. What does the brain of a grown person usually weigh? What 
are its chief parts ? How joined to the spinal cord? How do they 
lie in the skull ? Relative size? What are the cerebral hemispheres? 
How are their surfaces marked ? Name of the ridges? 



THE SPINAL CORD— THE NERVES. 



195 



its hinder end laps over it. A deep groove runs along the 
cerebrum from front to back and nearly cuts it in two. 
Its halves are named the right and left cerebral hemi- 
spheres^ and their surfaces are not smooth but are marked 
by numerous crooked furrows, with ridges between (Fig. 
53). The ridges are known as the convolutions. 




Fig. 53.— The brain from the left side. Cb, the cerebrum, or, rather, the left 
cerebral hemisphere; Cbl^ the cerebellum; Mo^ the medulla oblongata. 

6. The Spinal Cord is nearly round, and is about three 
quarters of an inch across and seventeen inches long. 
It does not reach as far as the lower end of the back-bone. 

7. The Nerves start from the brain and spinal cord. 
Twelve pairs {crcmial nerves) are attached to the brain and 
go out through holes in the skull; thirty-one pairs [spinal 
nerves) spring fi:om the sides of the spinal cord, and pass 
out between the vertebrae. 



6. Describe the spinal cord. How far does it reach? 

7. Whence do the nerves start ? What is said of the cranial nerves ? 
Of the spinal? Of the nerve fibres? Describe the branching of 
nerves. 



tgO 



SENSOl^y AND MOTOR NERVES. 




Each nerve is made up 
of a number of very slen- 
der threads, named nerve- 
fibres^ which run side by 
side in it like the threads 
in a skein of silk. As a 
nerve is followed along 
from its centre, it is found 
that it separates into small- 
er bundles of fibres, which 
run off as branches. These 
branches again divide, and 
so on, until the last branches 
are very small and very 
numerous. 

8. Sensory and Motor 
Nerve-Fibres. — A telegraph- 
wire is used to send mes- 
sages both ways. The same 
wire will carry a message 
just as readily from New 
York to Chicago as from 
Chicago to New York. Our 
nerve-fibres are not used 
in this way. Some of them 
are always employed to car- 
ry messages to the centres, 
others to carry messages 
f7'om the centres. The fibres 

8. Point out an important differ- 
ence between the carrying of mes- 
sages by telegraph-wires and by 
nerve fibres. What is meant by 
sensory fibres ? By motor ? 



REFLEX MOVEMENTS. 197 

which carry towards a centre are usually called sensory 
fibres, because when they work they very often cause 
some sensation or feeling. The fibres which carry from 
a centre are named motor fibres, because they usually 
cause some muscle to contract, and thus produce move- 
ment. The first set of nerves is also sometimes called 
afferent (from a Latin word meaning bringing to), and 
the other set efferent (from a Latin word meaning to 
bring from). These names are better than sensory and 
motor, because many nerves carry messages to centres 
without our having any sensation of them, and many 
nerves carry messages from centres to other organs than 
muscles, for example to glands. 

9. Reflex Movements. — As we have seen, a great deal 
of the orderly working of our organs is brought about 
without our will, or even without our knowing about it. 
When a message comes to a nerve-centre, the centre does 
not merely send out random messages along any outgo- 
ing nerve-fibres, but, as it were, first selects the organs 
to be set at work, and then sends the proper messages. 
As, for instance, in the case of sneezing. If the centre, 
warned by the sensory nerves of the nose, should set at 
work any or every outgoing fibre joined to it, the result 
would not be a sneeze, but some sort of a shaking-up or 
convulsion of the whole body. It might once in a thou- 
sand times be useful, but in most cases would do more 
harm than good. The disease known as " convulsions" 
is due to the fact that the nerve centres, whenever a 
nerve-fibre brings a message to them, send out random 

9. How is the involuntary working of our organs managed by the 
nerve-centres ? Illustrate from the case of sneezing. What happens 
if the nerve-centres send out messages to the wrong organs ? To 



198 REFLEX MOVEMENTS, 

messages to all the muscles instead of only to those 
whose contraction would be useful. 

Nerves merely carry messages to and fro. Nerve- 
centres do much more than this; they guide the mes- 
sages to the various organs, and, in all ordinary circum- 
stances, make them work for the general welfare of the 
body. Most nerve-centres do this independently of our 
will; they set the proper muscles at work whether we 
like it or not, though the cerebrum, which is the largest 
nerve-centre and only one where the will acts, sends 
out most of its messages in answer to the will. When 
food goes the wrong way and gets into your larynx 
(p. 168) you cannot help coughing; when something 
comes rapidly close up to your eye you cannot help 
winking; when you chew food you cannot prevent your 
salivary glands (p. 109) from pouring out extra secretion. 
All such useful movements, guided by nerve-centres, and 
not dependent on our will, are known as reflex movements. 
Sometimes we notice them, though we cannot hinder 
them, but far oftener we know nothing about them. 
These unconscious reflex movements, guided by the 
nerve-centres, carry on nearly all the regular daily work 
of the body necessary to keep it alive. They regulate 
the circulation and the breathing, and the secretion of 
the digestive liquids, and so on. The medulla oblongata 
especially regulates the beat of the heart and the breath- 
ing movements; if it is seriously injured, death occurs 
very quickly. 

If we had to think about and will every beat of the 

what are '^ convulsions" due ? What is the function of nerves? Of 
lierve-centres ? How do most nerve-centres behave as regards our 
will? Illustrate. Explain what is meant by reflex movements. What 
is said of our consciousness of them ? Of their use ? 



FEELING AND WILLING. 1 99 

heart, and the drawing of every breath, and the secre- 
tion of digestive fluids in the proper amount at the 
proper moment, and the blood-flow through each organ 
according to its needs at that time, and so forth, our 
minds would have time for nothing else. All this daily 
routine is looked after by nerve-centres which act in- 
voluntarily, and leave the mind free for other duties. 

10. Feeling and Willing. — The spinal cord, the medulla 
oblongata, and the cerebellum direct unconscious and 
involuntary movements. The cerebrum guides some 
such movements, but it does more: it is connected in 
some way with feeling and willing. No part of the body 
which is not joined by at least one nerve-fibre to the 
cerebrum, has feeling ; and no muscle not joined to it in 
like way, can be controlled by the will. 

For example, the nerve-fibres coming from the leg all 
unite, above the hip, into three or four large cords, which 
enter the spinal cord near its lower end. If all the 
nerves be cut at the ankle, the foot loses feeling, and all 
the muscles in it are paralyzed; that is to say, cannot be 
made to contract by their owner when he wishes. If 
only some of the nerve-fibres going to the foot be cut, 
then only that part of it to which the divided fibres went, 
loses feeling and has its muscles paralyzed. If all the 
nerves be cut at the knee, instead of the ankle, then both 
the foot and the lower part of the leg become insensible 
and paralyzed. If they be divided or crushed at the hip- 
joint, then the thigh also is put in the same condition. 

lo. What centres direct most involuntary movements ? What part 
of the body is especially concerned in feeling and willing? What is 
said of muscles and other parts not joined to the cerebrum by a nerve- 
fibre ? Illustrate from the results of injuries to the nerves of the leg 
at the ankle. The knee. The hip. What results when the sp-inal 



200 THE SYMPATHETIC NERVOUS SYSTEM, 

If the nerves of the leg be not injured at all, but the 
spinal cord be cut or seriously diseased above the place 
where they join it, the leg loses all feeling and has its 
muscles paralyzed just as if its nerves themselves were 
cut. The reason of this is that the nerve-fibres which 
run up the spinal cord to the cerebrum and cause feel- 
ing, and those which run down from the cerebrum to 
the leg and make its muscles obey the will, have been 
divided. The spinal cord, in addition to being a centre 
itself for many reflex movements, is a sort of nerve: it 
affords a path for many nerve-fibres which run between 
the cerebrum and most parts of the body. 

11. The Sympathetic Nervous System. — In addition to 
the great system of nerves we .have been studying, which 
branches out from the brain and spinal cord, and then 
divides and divides until it reaches every organ, and 
covers the surface of the body as closely as the capilla- 
ries (p. ) do, so that the prick of a pin-point must 
touch one of the little branches — in addition to this great 
set of cerebro-spinal nerves there is another, called the 
sympathetic system. The nerves of the sympathetic system 
are not spread through the skin or concerned in the 
sense of touch; nor are they subject to the will and con- 
cerned in producing voluntary movements. But they 
go to the lungs, and the heart, and the liver, and the 
stomach and intestines, and to the involuntary muscles 
(p. 42). They do not run direct to the brain and spinal 
cord, but first to certain smaller centres, lying principally 

cord is cut above where the nerves of the leg enter it ? Why ? What 
is the spinal cord in addition to being a centre ? 

II. What is said of the nerves connected with brain and spinal 
cord ? Of the nerves of the sympathetic system ? What is a gangli- 
pn ? Why so named ? What is the sympathetic system ? Its duties ? 



MIND AND BRAIN, 20I 

in two rows in front of the spinal column (j*, Fig. i). 
Each of these small centres is named 2i ganglion^ which is 
the Greek word for a swelling. This name has been 
given them because they make swellings on nerves like 
knots on a string. Th.^^^ ganglia are joined to one an- 
other and to the brain and spinal cord by nerves. They, 
with the nerves running to and from them, look after a 
good many of the details of the working of the body. 
The sympathetic system is a sort of under-servant of the 
brain and spinal cord, trusted to look after certain routine 
work, especially the distribution of the blood among the 
various organs, according as their needs may be. It has 
also much to do with managing the glands. It owes 
its name to the fact that it makes many organs which 
are not under direct control from the will, work together, 
as if they sympathized with one another. 

12. Mind and Brain. — The cerebrum is not only con- 
cerned in feeling and willing, but in remembering and 
reasoning, and in all the other things which go to make 
up what we call mind and character. How mind is con- 
nected with brain it is not possible to imagine ; we have 
just to accept the fact that it is, and especially its fur- 
rowed and ridged surface. When this is seriously dis- 
eased, feeling is lost or unnatural, the will is enfeebled, 
memory weakened, reason impaired, and the man no 
longer capable of judging correctly, nor really responsible 
for his actions. Why, or how, we do not know, and 



12. With what besides feeling and willing is the cerebrum con- 
cerned ? What is said of the connection of cerebrum and mind ? 
What part of the cerebrum has especially to do with mind ? What is 
seen when it is seriously diseased ? What is it sufficient to know 
concerning the connection of brain and mind, for all practical pur- 
poses ? 



202 MIND AND BRAIN. 

probably never will know. However, for all practical 
purposes, it is sufficient to know that, if we desire active 
and vigorous minds, we must try to keep healthy brains; 
we may then consider all the knowledge we can get 
about the hygiene of the brain as coming, in the long- 
run, to the same thing as hygiene of the mind. 



CHAPTER XIX. 
HYGIENE OF THE NERVOUS SYSTEM. 

1. Introductory. — The nervous system is so closely 
connected with all other parts of the body that any- 
thing which injures them can hardly fail to hurt it. He 
who desires an active healthy nervous system and a 
vigorous cheerful mind, must strive to keep muscles and 
digestive, circulatory, and respiratory organs in health. 

On the other hand it should be borne in mind, that 
nearly every function of the body is dependent on the 
nervous system for its proper performance. It sets at 
work the muscles which move the jaws, and the glands 
which secrete saliva; controls the oesophagus in swallow- 
ing; excites the glands of the stomach, and makes its 
muscular coat mix the gastric juice with the food; it 
governs the secretion of pancreatic juice and bile, which 
turn the chyme into chyle; makes the muscular coat of 
the intestine drive the digesting mass along that tube, 
and controls absorption by its lacteals and blood-vessels; 
it regulates the beat of the heart, and the diameter of 
the arteries^ and, thus, the blood-flow to every organ; it 

I. What is said of the connection of the nervous system with 
other parts of the body ? What must one do who desires an active 
nervous system and mind ? What should also be borne in mind ? 
Give illustrations of the action of the nervous system in preparing 
food to enter the stomach. In controlling its digestion in the stom- 
ach. On conversion of chyme into chyle? On the movements of 
the intestine? On absorption? On the blood-flow? On excretion ? 



204 SOME NERVOUS DISEASES. 

keeps in action the lungs, and skin, and kidneys to 
purify the blood; it makes the eye see and the ear hear; 
and through it we think, and hope, and love. To injure 
the nervous system by too much work, too little sleep, 
or over-indulgence in tobacco, alcohol, or any other sub- 
stance which affects it, is to weaken every function of 
the body and the mind. 

No doubt many persons have attained intellectual 
eminence and led happy and useful lives in spite of 
bodily feebleness. Unusual strength of will has enabled 
them to overcome the odds against them. But we 
should remember that body and mind are so unit'='d 
that any disease of one affects the other, and she ild 
guide our conduct accordingly. 

2. Some Disorders of the Nervous System. — Unhappily 
most children have seen cases of ^' St, Vitus Dance.'' It 
is a twitching of the muscles, sometimes only those of 
the face, sometimes those of the limbs and body gener- 
ally. It comes from weakening of the control of the 
nervous system over the muscles, so that occasionally 
some muscle relaxes. This enables the opposing muscle 
to give a jerk and pull the organ, it may be the eyelid, 
the mouth, the arm, or the leg, out of place. Sometimes 
these jerkings are so violent as to seriously injure the 
organs. 

Fits is a name given to several disorders attended with 
loss of consciousness, h. fainting fit is due to temporary 
weakness of the heart; it pumps so little blood around 
that the cerebrum does not get enough nourishment to 

What are the consequences of injuring the nervous system ? What 
have some persons of feeble body accomplished ? How ? What 
should we remember ? 

2. What is St. Vitus' dance? To what due ? To what is ^ fainting 



FAINTING,— HYSTERICS, 205. 

enable it to work. A person who has fainted should be- 
laid at once flat on the back, with the head low; this^ 
enables blood to be pumped more easily to the brain. 
The skin may then be stimulated by sprinkling the face 
briskly with cold water, or the nose by holding harts- 
horn to the nostrils. The convulsions so common amotlg 
infants are in most cases excited by some irritation cotl= 
nected with the alimentary canal. An emetic should be 
given at once, cold applied to the head, and the body 
put in a warm bath. In epileptic fits there is usually a 
peculiar cry, the face becomes pale, consciousness is 
lost, and then convulsions (p. 98) occur. Lay the per- 
son flat, and restrain any of his movements likely to in- 
jure him. If possible, a folded handkerchief should be 
pushed between the teeth to prevent biting of the 
tongue. After the convulsions have ceased, quiet is de- 
sirable. Hysterical fits assume many different forms, the 
more frequent perhaps being unreasonable screaming, 
laughing, and weeping by turns. They should be 
noticed as little as possible. A display of interest and 
sympathy nearly always makes a fit of hysterics last 
longer. A little rudeness, exciting anger, is often the 
best treatment. 

k.x\ apoplectic fit or apoplexy \s due to the bursting of 
some blood-vessel of the brain. The blood which flows 
out compresses the brain, and the person becomes more 
or less unconscious. The breathing is heavy and like 
snoring, and the face usually flushed. A person suffer- 
ing from an apoplectic fit should not be moved at all if 

fit due? Treatment. What is said of the convulsions of young chil- 
dren? Characters of an epileptic fit? What is said of hysterical fits ? 
Cause of an apoplectic fit ? Symptoms ? What is said of the manage- 
ment of a person in an apoplectic fit ? What is neuralgia ? On what 



2o6 I^EURALGIA. 

it can be avoided; apply cold to the head until medical 
aid can be obtained. 

Neuralgia is a diseased condition attended with in- 
tense pain, which may attack almost any part of the 
body. It seems to depend on an altered or disordered 
state of the nerves themselves, for usually nothing can 
be found wrong in the organ in which the pain is felt. 
Thus the teeth or the stomach may appear to be perfect- 
ly sound in their structure, and yet suffer intensely from 
neuralgia. The almost unbearable pain often leads to 
the use of alcohol, opium, and chloral (Chap. XX.), drugs 
which, while giving temporary relief, tend to increase 
the diseased condition of the nerves. Some persons 
have organizations more nervous than those of others, 
and under unfavorable conditions of life are very apt 
to become victims of neuralgia. These persons may 
be recognized by their tendency to undertake more 
than they have the strength to perform safely, and to 
be extreme in all their feelings. They should guard 
against lives of excitement, and be careful to secure 
plenty of sleep, and not to allow themselves to be over- 
driven by ambition. 

3. The Three Great Sources of Nervous Health are a 
brave heart, a cheerful disposition, and plenty of sleep. 

Nothing wears the nerves like worry. The child at 
school who keeps a brave heart for whatever may hap- 
pen stands a better chance of success than the one who 
wears his nerves out with constant dread of failure. One 

does it depend ? Illustrate. To what does it often lead ? How 
may persons apt to become neuralgic be recognized ? What precau- 
tions should they take ? 

3. What are the three great sources of nervous health ? What is 
said of worry ? Of the effect of a brave heart in promoting success ? 
Of the benefits of a cheerful disposition ? 



SLEEP. 207 

who has a cheerful disposition and a sunny temper is not 
only unlikely himself to suffer from nervous ailments, 
but, by a contagious influence, helps to keep others well 
and happy. 

4. Sleep, however, sound and plenty of it, is the one 
great condition of nervous health. Tlie use of sleep is to 
give the cerebrum a period of complete rest, for growth 
and repair. While awake, even when we are not doing 
brain-work, the mind and cerebrum are in action all the 
time; feeling and willing and thinking. Perhaps not 
feeling much or willing much or thinking hard, but still 
doing some or all of those things every moment. So long 
as we are conscious, the mind and cerebrum are at work. 
Healthy sound sleep is a state of the body in which the 
cerebrum is entirely at rest and there is no conscious- 
ness. A due amount of it is as absolutely necessary for 
a healthy brain and mind, as periods of rest are for the 
muscles or stomach. 

5. The Amount of Sleep Necessary for Health varies 
with age and employment. Children need more sleep 
than older persons, and those whose chief work is men- 
tal, need more than those whose work is muscular. 

The brain of a child has to grow and develop and is 
easily fatigued; it needs plenty of the deep thorough 
rest given by sleep. Moreover the muscles of a healthy 
boy or girl are full of life, and need abundant exercise. 
This makes severe mental work dangerous (p. 57). The 
organs which nourish the body, can only in a few 
favored persons provide at the same time for the needs 

4. What is the use of sleep ? What is said concerning mind and 
cerebrum during waking hours? What is healthy sound sleep? 

5. What persons need most sleep? First reason why children need 
more than adults ? Another reason ? What is the usual result of 



208 MENTAL EXERCISE, 

of acLivv^ growing muscles and hard-worked nervDus 
systems. The attempt to make them do so, is very apt 
to stunt and injure both. As we grow older, and the 
demands of the body for extra materials for its growth 
become less or cease, more steady.and continued brain- 
work can be undertaken with safety and benefit. 

The ** soundness*' of the sleep is important. Five or 
six hours of thorough deep sleep, with no dreams or 
consciousness of any kind, are better than eight or nine 
hours of uneasy sleep. Sleepnessness {insomnia) is a 
very serious matter; if continued or frequent, medical 
advice should be obtained. Unless checked, it leads to 
exhaustion of the brain, and impairment of the mind. 

6. The Brain Needs Exercise. — If the body in general 
is healthy, the involuntary nerve-centres will look after 
their own work, and take proper exercise and rest ; but 
the part of the brain concerned with mental work is 
more under our control, and may be harmed by over- 
work or idleness. It is made stronger, and the mind 
more vigorous, by regular exercise. 

When one first begins to train his muscles to do any 
special task, they soon tire, but after a time the work 
becomes easy, and more difficult feats can be under- 
taken. In like way, mental work is apt at first to be 
very fatiguing, but regularly repeated, with proper in- 
tervals of rest, it becomes easier every time; and soon 
harder tasks can be accomplished, and even enjoyed. 

trying to work hard with both brain and muscles ? What is said of 
sound sleep as compared with restless ? Of sleeplessness? 

6. What do the involuntary nerve-centres do in health ? What 
part of the nervous system is more in our control ? What is the 
effect of exercise on the mind ? What is the result of training the 
muscles ? The mind ? What is said of the effects of idleness on the 
mind? 



MENTAL EXERCISE, 2Q§ 

An idle mind, like idle muscles, becomes Weak. Even 
if it remain in a few cases shrewd and clear, it is inca- 
pable of prolonged steady effort, such as may any day 
become necessary. There are mental loungers as well 
as muscular; and the former are rather the more con- 
temptible. 

7. Mental Exercise should be Varied. — You have learned 
(p. 57) that a man may exercise and greatly develop 
some of his muscles, and leave others idle and feeble. 
A great many people do something of this kind with 
their brains. They use and train some mental faculties 
and leave the rest unemployed until they almost cease 
to be active at all. The hard struggle which most of 
us have, nowadays, to make a place for ourselves in the 
world and keep it, is very apt to lead to this mental lop- 
sidedness, which is as much a deformity as would be 
huge arms and spindling legs on the same body. We 
meet business-men so absorbed in money-getting that 
they care for no books except ledgers, no science unless 
it helps them to patent some invention. We meet men 
of science who take no interest in art or literature, or 
who affect to despise the business-men who are carry- 
ing on the great commerce which promotes the progress 
of the world in ten thousand ways. We meet literary 
men who seem quite incapable of sympathy with science, 
and artists who care for nothing outside of art. All 
such people may be very far from insane, in the usual 
sense of the word, but they are all mentally deformed. 

7. How do some people train their mental faculties ? What often 
leads to mental lopsidedness? To what is it compared? Give illus- 
trations of persons who use only a small part of their mental faculties. 
What is said of mental deformity ? Why is a broad education in 
€arly life very valuable ? 



2IO BRAIN-REST, 

Some are born so and cannot help it, but a great many 
have made themselves so by persistently neglecting to 
use many of their intellectual faculties. 

After a man gets settled down to his business, what- 
ever it be, he rarely has much time or energy to devote 
to other things. Hence arises the value of a broad edu- 
cation in early life, tending to widen the range of our 
sympathies and interests. 

8. Education. — All education worthy the name, not 
merely supplies instruction in certain things useful to 
know, but trains the will and strengthens the character. 
For this reason it should include the performance of un- 
pleasant or difficult duties. Every man and woman has 
to face many such duties in the course of life, and the 
will must be made strong to meet them. A school where 
every study is made easy and pleasant may be popular, 
but it is not the best school to turn out real men and 
women, strong to play a noble part in life. 

9. The Brain Needs Rest as well as Work. — Overwork, 
giving no sufficient periods of rest for repair of the 
nerve-substance destroyed during activity, harms the 
brain very much in the same way as it does the muscles 
(p. 52). The results of mental overwork are, however, 
apt to be far more disastrous than those of muscular. 
Muscles which have been exercised too much usually re- 
cover completely with rest and nourishment, and become 
as strong as ever : a brain which has given way under 
overwork, is very apt never again to be as capable of 

8. What does all good education do? Why should it include diffi 
cult tasks ? Why must the will be made strong ? 

9. What is said of overwork of the brain ? Why worse than of the 
muscles? What are the mental symptoms of an overtaxed brain? 
How is the body in general affected by it? How does it often lead 
to drunkenness ? 



BRAIN-REST. 211 

eontinued labor as it would have remained, had it been 
used wisely. 

Apart from mental symptoms, as sleeplessness, con- 
fusion of thought, low spirits, loss of memory, and inca- 
pacity for prolonged steady thought, an overtaxed brain 
acts on the whole body and injures it. The digestion 
especially is impaired, and this of course brings in its 
train many evils, due to ill-nourishment of various organs 
(see pp. 123-4). The feeling of lassitude and exhaustion 
causes a longing for stimulants, which give temporary 
relief, and many a man has thus become a drunkard. 

10. Brain-Rest Obtained by Change of Employment. — 
There is an old saying that '* change of employment is as 
good as rest;" properly understood it is a very true one. 
The change, however, must be thorough. It is not of 
much use for a business-man to go, in search of rest, 
from New York to Saratoga and there continue his busi- 
ness by correspondence; nor for a child to change from 
studying history to arithmetic. Unless the change is 
accompanied by a sense of recreation and pleasure, it is 
of little or no value as affording brain-rest. Doing noth- 
ing is often wearisome to persons who have never formed 
habits of idleness; when the minds of such need rest, 
they should seek some occupation calling for little exer- 
cise of the faculties employed in their regular daily 
work, and which yet interests and amuses them. 

11. Concentrating One's Thoughts. — ^^One of the hardest 
things a child has to learn, is to *^ fix its attention," or 

10. What is necessary that change of employment may rest the 
mind ? Illustrate. What should accompany the change ? What 
should those seek who soon weary of doing nothing and yet need 
brain-rest ? 

11. What is said of fixing the attention? Illustrate. How may the 
power be acquired ? Why should the training be gradual ? 



212 ACTION OF ALCOHOL ON NkkVOV^ SYSTEM. 

keep its mind from being distracted and wandering off 
to other things. A great many grown people, indeed, 
cannot do it. A very distinguished American lecturer, 
writer, and anatomist,* has stated that he could gauge 
the intelligence of his audience by the way in which 
they behaved when any slight disturbance occurred 
during his lecture. On an educated audience, with 
trained power of attention, any slight noise had little 
influence, while less educated hearers turned their heads 
at every trivial interruption. 

To acquire this power of attention, is most important. 
Probably no young healthy child has it; it must be 
gained by prolonged training, but the training should 
be gradual. A young child cannot fix its mind on a 
lesson, no matter how easy, for an hour at a time. 
Short lessons, with frequent brief intervals in which the 
attention is permitted to relax, should be given at first. 

12. The Effects of Alcohol on the Nervous System and 
their Symptoms. — Alcohol is a terribly frequent cause of 
nervous diseases. In over-stimulating the brain and 
spinal cord, it impairs their structure, weakens their 
functions, and often leads to insanity and crime. 

A small quantity of wine or spirits, taken by one not 
accustomed to it, congests and excites the brain; the 
person gets restless and talkative, then dizzy and unable 
to think clearly. He is soon overcome by sleep, and on 
awaking feels out of sorts. 

If the dose be increased, the talkativeness is accompa- 

12. What is the action of alcohol on the brain and spinal cord? 
What is the action of a glass of wine on a person not used to it ? 

* Professor Oliver Wendell Holmes. 



NERVOUS ALCOHOLIC DISEASES. 213 

nied by indistinct speech and the dizziness by trembling 
hands and a staggering walk, both showing loss of con- 
trol over the voluntary muscles and the will. The sense 
of touch is dulled; the eyeballs do not move together, so 
as to look exactly at the same point at the same moment, 
and objects, accordingly, appear double. (You may imi- 
tate this effect by pushing one eyeball gently while 
looking with both eyes at something.) Then follows 
profound drunken sleep, which may pass into " coma,'* 
a condition of deep unconsciousness from which the 
person cannot be aroused, and in which the breathing is 
slow and labored because the involuntary nerve-centres 
which govern the breathing-muscles are affected. Some- 
times these centres become at last quite paralyzed and 
death results, but more often the man sleeps off his 
drunken fit, to awaken with a state of his nerves to be 
relieved only by renewed drinking, followed each time 
by worse results. 

The nerve-centres, however, soon get used to the 
stimulant; it takes a larger amount each time to make 
them unsteady, but all the while brain and spinal cord 
are becoming surely, if slowly, diseased. 

13. Some of the Nervous Diseases due to Alcohol. — Deii- 
riu7n tremens (trembling madness) is a frightful form of 
temporary madness, accompanied by great trembling. 
The senses are partly lost; the man sees spectres, usually 
foul and horrible, about him, and has all sorts of terrify- 
ing visions. He is at times violently excited and raving 

What if the amount be increased? What is coma? Why is the 
breathing labored during coma? What may result? Why is one fit 
of drinking likely to lead to another? Why does it need more alcohol 
to make a practised toper drunk? 

J J. What is delirium tremens ? Its symptoms ? Its causes? Dip- 



214 NERVOUS ALCOHOLIC DISEASES. 

mad; in the intervals, utterly prostrate, sleepless, and a 
prey to indescribable terrors of the imagination. 

Repeated drunkenness usually ends in an attack of 
this disease, but it is more frequently the result of con- 
tinued hard drinking in persons who have never become 
actually drunk. It is especially apt to occur in those 
who drink to ^' keep them up" while engaged in hard 
mental work. 

Dipsomania is a diseased condition, often only showing 
itself at long intervals, and marked by a mad passion 
for alcohol. However disgusting a liquid containing 
alcohol may be, the dipsomaniac will swallow it greedily. 
While the fit is on him he is as irresponsible as a mad- 
man, and his only safety is in being restrained as one. 

This disease is sometimes produced by indulgence in 
drink, but is more often inherited from parents who 
have been drunkards. Sufferers from it are entitled 
to sympathy to which the common drunkard has no 
claim. 

FaralysiSy epilepsy^ and insanity often result from drink- 
ing. There is, in fact, no kind of madness or of nervous 
disease which may not be, and has not been over and 
over again, produced by alcoholic drinks. Many of 
these diseases have other causes also, but none so fre- 
quent as alcohol. 

Perhaps the greatest evil of intemperance is that the 
drunkard so often transmits to his innocent children 
some form of nervous disease. In the families of such 
are found the weak in body, weak in mind, weak in will, 

somania? Symptoms? Treatment? Cause? Name other nervous 
diseases produced by drinking. What is said of the causes of mad- 
ness and nervous diseases ? Of the transmission of such diseases to 
a drunkard's children ? What do we find in the families of drunkards ? 



NERVOUS ALCOHOLIC DISEASES, 21 S 

weak in character: the epileptic, the rickety child, the 
half-witted, the idiot, the dipsomaniac, the maniac; 
children who grow up unable to honestly make their 
way in the world, and become public burdens in insane 
asylums, prisons, or poorhouses. 



CHAPTER XX. 
NARCOTICS. 

1. Narcotics. — Certain drugs have the power of making 
the cerebrum unable to work for a time; they thus cause 
unconsciousness, and produce what seems to be sound 
sleep. Substances which act on the nervous system in 
this way, are named narcotics. In small doses, they often 
relieve pain without causing actual loss of conscious- 
ness. Chloroform, chloral, ether, opium, laudanum, and 
morphia are examples of narcotics. Tobacco may be 
included, since, when not taken as a mere idle luxury, it 
is employed to soothe the nerves. Alcohol in large 
doses is also a narcotic. Occasionally, in a crisis of dis- 
ease, when sleep must be obtained at any cost, or terrible 
parn is wearing out the strength of the sufferer, a nar- 
e®tic, carefully ordered in proper dose by a physician, is 
a very valuable medicine. Taken habitually, narcotics 
weaken the mind, injure the whole nervous system, and 
cause many diseases. 

2. Opium and Morphia. — Opium is a gummy mixture 
obtained from a kind of poppy. Its chief active prin- 
ciple is morphia. The forms in which opiates are most 
used are: (i) gtivi opimn, the natural substance, often put 

1. What power have narcotics ? What if taken in small dose ? 
Give examples of narcotics. When is tobacco one ? Alcohol ? 

2. What is opium j* Morphia? What are th^ commonest forms of 
opiates ? 



OPIUM-EA TING, 2 1 7 

up in the form of pills; (2) laudanum^ made by dissolving 
opium in alcohol; (3) paregoric^ a liquid containing sev- 
eral ingredients, of which opium is the most important; 
(4) morphia, and solutions containing it. 

3. The Opium Habit. — Opium is perhaps the most 
valuable drug at the disposal of the physician. On the 
other hand, it is one of tlie most hurtful substances used 
by mankind. It may be that it does not do as much 
harm in the United States as alcoholic drinks, but only 
because not so many persons have taught themselves to 
crave it. Used constantly, it is as surely fatal, and the 
habit is perhaps even harder to break, for it may be in- 
dulged more secretly, and its effects are not so readily 
recognized. There is this, also, to be said: most of 
those who kill themselves by drink are persons of weak 
will, while many a one of highest gifts and noblest char- 
acter, who would loathe the low vice of drunkenness, has, 
before knowing the danger, become the hopeless victim 
of opium. Using the drug, at first, as ordered by a 
physician for the relief of pain, he (or she, for more 
women than men are given to opium-excess) is scarcely 
conscious of danger, until the repeated employment of 
the drug has created an almost irresistible craving for its 
continuance. Most medical men now fully recognize 
the danger, and only order prolonged use of opium with 
great caution. 

4. The Diseased Conditions Produced by Regular Use 
of Opium, — The first effect is deadening of sensibility, 
accompanied by mental exaltation, if the dose be small. 

3. What is said of opium ? Of its harmfulness as compared with 
alcohol ? Why is opium more disastrous from one point of view ? 
How is it now given by physicians? 

4. What are the first effects of a dose of opium? What is the con- 



2l8 EFFECTS OF OPIUM ON HEALTH, 

This is succeeded by unnatural sleep, disturbed by fan- 
tastic dreams. 

On awaking, there is great depression of mind and 
body: often associated with defective memory, and a 
feeling that something terrible is about to happen. 
There is muscular weakness; distaste for food, without 
actual nausea; and an almost irresistible craving for an- 
other dose. 

If the habit be continued further, mental and physical 
changes occur. Distaste and inaptitude for any kind of 
exertion; weakened digestion; not enough secretion of 
bile; slow action of the muscles of the bowels, causing 
constipation. The voluntary muscles waste, the skin 
shrivels, and the person gets the appearance of old age 
prematurely. The pulse is quick, the body feverish; 
the eye dull, except just after taking a dose of the drug. 

Next comes failure of the nervous system. The legs 
are partly paralyzed, and then the muscles of the back. 
The victim crawls along, bent like an old man. Death 
finally results from starvation, due to complete failure in 
the working of the digestive organs. 

5. Morphia or Morphine. — When morphia is used, a 
solution of it is usually injected under the skin by a 
sharp-pointed syringe. Continued use of it in this w^ay 
is followed by all the symptoms of opium-poisoning 
above described, and has the same fatal ending. The 
digestive organs are not so quickly injured; but, on the 
other hand, the repeated punctures of the skin cause in- 
flammation and sores. 

dition of the person on awaking ? What results follow continuance 
of the habit ? How does opium affect the nervous system ? 

5. How is morphia usually given ? Results of its continue4 vse ? 
Compare its effects with those of opium. 



CHLORAL. 219 

6. Danger of Administering Opiates to Children. — 

Children are extremely easily poisoned by opium and all 
things containing it or morphia. They should never be 
given to a child except on the order of a physician^ and exactly 
as ordered. Many an infant has been killed by paregoric 
or some ^' soothing syrup" containing opium, given, with- 
out medical advice, by a parent or nurse to stop diar- 
rhoea or produce sleep. 

7. Chloral, Chloral Hydrate, Syrup of Chloral. — A few 
years ago, chloral was proclaimed a wonderfully harm- 
less narcotic: it caused sleep or lessened pain without 
harm, it was said, to mind or body. Physicians have 
since learned that it is not at all the harmless drug they 
formerly believed it, but many other people have not yet 
had their eyes opened to its dangerous character. Vari- 
ous preparations containing it are sold in drugstores to 
any one asking for them; and many persons who would 
hesitate to take opiates without medical advice, use^ 
cliloral, believing it quite safe and harmless. 

Chloral, taken habitually, is at least as mischievous as 
opium. To retail it in any form except on the prescrip- 
tion of a physician, should be made illegal. . 

The chloral habit is acquired with great ease, and is 
very hard to break. The first phenomena of chloral dis- 
ease {chloralis??i) are these: The digestion is greatly im- 
paired; the tongue is dry and furred; there is nausea; 
sometimes vomiting, and a constant feeling of oppres- 
sion from wind on the stomach. 



6. Why should opiates never be given to a child except by a physi- 
cian*s order? What has resulted from neglect of this precaution? 

7. What was believed of chloral a few years ago ? What have 
medical men lately learned about it ? Why do so many people take 
chloral without medical advice ? Describe the first symptoms of 



220 BROMIDES, 

Next, nervous and circulatory disturbances occur. 
The temper becomes irritable, the will weak; the hands 
and legs tremulous; the heart-beat irregular; the face 
easily flushed. Sleep becomes impossible without use 
of the drug, and when obtained is troubled, and the per- 
son awakes unrested. 

In later stages, the blood is seriously altered. Its 
coloring matter is dissolved out of the corpuscles into 
the plasma (p. ), and then soaks through the walls of 
the capillary vessels, causing purplish patches on the skin. 

If the chloral-taking be stili continued, death results 
from impqvished blood, weakened heart, or paralysis of 
the nervous system. Not unfrequently, chloral-takers 
unintentionally commit suicide by indulging in too large 
doses. 

8. Bromides. — The drugs included under this name, 
resemble chloral and its compounds in that they were 
once regarded as safe soothers of the nervous system and 
promoters of sleep, that physicians have now learned that 
they are very dangerous w^hen frequently used, and that 
the general public still believe them safe, and often use 
them without a doctor's advice. They are very valuable 
medicines in some circumstances, but do just as much 
harm, when taken indiscreetly, as opium or chloral. 
Some mothers and nurses who have learned the danger 
of paregoric and soothing syrups, now give bromides 
instead to restless infants. The bromide is just as 
dangerous as the opiate, and should never be given to 
child or adult except on a doctor's prescription. 

chloralism. What are the symptoms in more advanced chloralism ? 
What in the latest stages ? 

8. In what do bromides resemble chloral ? What are the dangers 
of using them ? What precautions are necessary ? 



TOBACCO. 221 

9. Tobacco is often indulged in for the sake of soothing 
the nervous system or lessening the feeling of mental 
fatigue or worry. It also decreases the oxidations of the 
body, and its wasting, and so enables it to get along 
with less food; it may in this way be useful to a starv- 
ing or ill-fed person. It contains a small amount of an 
active principle, nicotin^ which is a powerful poison. A 
few drops of pure nicotin will cause rapid death by para- 
lyzing the heart. When tobacco is smoked, some of the 
nicotin is burned; but vapors containing ammonia are 
formed, and these irritate the mouth and throat. The 
ill effects of smoking are thus, in part, general — due to 
absorbed nicotin; and in part local — due to irritating 
matters in the smoke. It cannot be denied that many 
persons consume a good deal of tobacco without being 
much harmed by it. But it does no one any good unless 
he cannot get sufficient food, or his nervous system is so 
diseased or irritable that it needs soothing. One gen- 
eral rule may be laid down without fear of contradiction: 
tobacco is always very injurious to those whose bodies are not 
yet fully developed. 

10. The Local Action of Tobacco is at first manifested by 
an increased flow of saliva. After some practice in 
smoking this effect ceases, and is succeeded by a feel- 
ing of dryness in the mouth, which often leads to indul- 
gence in alcoholic drinks. In this perhaps lies the 
greatest danger from tobacco. The habitual smoker 
often suffers from what is well known to physicians as 

9. Why is tobacco indulged in ? When may its use be beneficial ? 
What is said of nicotin ? What becomes of it when tobacco is smoked ? 
The ill effects of smoking ? What general rule may be safely stated ? 

10. How does the local action of tobacco first show itself? How 
is this changed by practice in smoking? Point out one of the chief 



222 ACTION- OP TOBACCO. 

^^ smoker^s sore throat." This is accompanied by a hack- 
ing cough, and often with difficulty in speaking and some 
deafness. Cure is impossible unless smoking is given 
up. 

The smoke of the paper in which cigarettes are rolled 
especially irritates the throat and larynx. So far as 
these organs are^concerned, a cigarette is the most inju- 
rious form in which tobacco can be smoked. 

11. The General Action of Tobacco. — The absorption of 
nicotin and other substances contained in tobacco, is apt 
to interfere with the proper development of the red cor- 
puscles of the blood. This, as you have learned (p. 136), 
is a very serious evil, because these corpuscles have to 
carry oxygen all through the body for use by the differ- 
ent organs. As a result of their deficient quantity, not 
only does the skin grow pale, but all the organs do poor 
work. The muscles become feeble; the stomach digests 
badly; the heart is weakened and subject to attacks of 
palpitation; and the eyesight very often impaired. In 
general, there is produced a feeling of lassitude and in- 
disposition to exertion of any kind that, in view of the 
heavy odds a man has to contend against in the struggle 
of life, may prove the handicap that causes his failure. 
If success in life be an aim worth striving for, it is surely 
unwise to shackle one's self with a habit which cannot 
promote and may seriously jeopardize it. 

dangers from tobacco. What is smoker's sore throat ? By what ac- 
companied ? What necessary for cure ? What is said of cigarettes ? 
II. Action of absorbed nicotin on the blood? Why serious? Ac- 
tion of nicotin on the muscles ? The stomach ? The heart ? The 
eyesight ? What is said of its effects in general ? 



CHAPTER XXI. 

THE SENSES. 

1. Common Sensation and Special Senses. — Each of us 
has a great vndiny feelings^ or sensations, of different kinds. 
We may be hungry or thirsty or tired or suffer pain in 
a variety of ways. Such sensations as these tell us 
about our own bodies. Hunger warns us to eat, nausea 
or ^* sickness" that the stomach is not in a condition to 
digest, pain that some part is diseased or injured and 
needs attention. All these kinds of feeling are named 
common sensations. 

Other kinds of sensations enable us to learn about 
things outside of our bodies, and to perceive and use ob- 
jects in the world around us. These sensations are 
known as the ** special senses;" they include sight, hear- 
ing, smell, taste, and touch, which are commonly spoken 
of as *^ the five senses." To these we should add the 
temperature'Sense, which often enables us to learn that 
something is hot or cold without touching it or seeing 
it. These senses have been well called the ^' gateways of 
knowledge," because without them the mind would have 
to remain in complete ignorance of the world and uni- 
verse in which we live. 

I. How do we learn the needs of our own bodies? Examples? What 
are ihese feelings called ? What is the use of the special senses ? 
Name the " five senses." What is the temperature sense ? Why are 
the senses called the gateways of knowledge ? 



224 SENSATIO.V DEPENDS ON THE BRAIN. 

2. All Kinds of Sensation Depend on the Brain. — You 
have already learned that when the nerve-fibres of the 
foot are cut anywhere on their way to the brain, the foot 
loses feeling (p. 200). This is true of every other part 
of the body which has feeling, whether it be merely a 
part possessing some common sensation, or an organ of 
one of the special senses. Also, if the brain be acted upon 
by chloroform or ether, or certain parts of it be seriously 
diseased or injured, feeling is lost, although the nerves 
and the sense-organs may be quite unaffected. We thus 
learn that all feeling is due to some change in the brain. 
Usually, when we have a sensation, whether of sight, 
hearing, pain, or any other kind, it is due to the fact that 
some sensory nerve (p. 196) has been set at work, and 
has carried a message to the brain. This message has 
then set at work, or excited, a part of the brain, which 
makes us see or smell; and so on. The mind has learned 
from what parts of the body these messages to the brain 
usually start, and w^e have come to think of each kind of 
feeling as being in the organ or place from which the 
message starts, and not in the brain itself. When the 
eye is closed we do not see, so we think the sense of 
sight is in the eye. Yet it really is in the brain: all that 
the eye does is, when light acts on it, to send messages 
along its nerve to the brain, and set to work that part of 
the brain which has feelings of sight; and so it is with 
our other senses. 

2. What results when all the nerve-fibres coming from any part of 
the body which has feeling, are cut ? How may loss of feeling be 
caused without affecting the sense-organs or the nerves ? What is 
thus proved ? To what is a sensation usually due ? What happens 
when the message sent by the sensory nerve reaches the brain ? 
How has the mind come to connect certain feelings with certain parts 
of the body ? Illustrate. What sometimes happens as regards sen- 
sations in disease ? Results ? 



THE ORGAN OF SIGHT, 22^ 

Sometimes in disease, the parts of the brain which give 
us feelings are excited without waiting for any message 
brought in along a sensory nerve. Then the person be- 
comes delirious or suffers from delusions. He sees and 
hears and smells things which do not really exist; but 
to his mind they are just as real as if they did actually 
exist, and were acting on his sensory nerves so as to ex- 
cite the parts of the brain which feel. 

3. Why the Eye is the Organ of Sight. — In the eyes there 
are thousands of nerve-fibres, each of which has a little 
** tip" or end on it which is so made as to be very easily 
acted on by light. Any light, as from the sun or a lamp 
or candle, which comes direct, or is first reflected from 
some object, and reaches one of these peculiar little ends, 
excites it, and the end in turn excites the nerve-fibre 
joined to it, and this fibre then carries up some message 
to the part of the brain which gives us feelings or sensa- 
tions of sight. If the light comes direct it excites the 
nerves in such a way that we see the sun or lamp or 
candle. If it comes bounding back from some other 
object which it has struck on its way, we see the other 
object. No other nerves than those of the eye have this 
particular kind of tips on their ends, and so light does 
not excite them, as it does the nerves of the eye. 

4. The Eyeball (Fig. 55) is nearly as round as a 
marble, but is buried in the eye-socket and covered by 
the eyelids, so that only a small part of its front side can 
be seen. On this front part is a round transparent win- 
dow, set in it, like a pane of glass, to allow light to get 

3. What is there on the ends of the nerve-fibres in the eye ? What 
happens when light reaches them ? Why cannot we use other parts 
of the body for seeing ? 

4. Describe the shape and position of the eyeball. What is there 



226 



THE EYEBALL. 



into it. To the inner or deeper side of the eyeball is 
attached the optic nerve^ 17, which runs to the brain, 
and is the nerve of sight. 

5. The Eyeball has Three Coats, an outer, a middle, and 
an inner. 

The outer coat is tougli and strong: on the back and 




Fig. 55.— The left eyeball in horizontal section, i, sclerotic; 2, junction of 
sclerotic and cornea; 3, cornea; 10, choroid; 14, iris; 15, retina; 17, optic nerve; 
26, 27, 28, are placed on the lens ; 29, vitreous humor ; 30, aqueous humor. 



sides of the eyeball it is opaque, that is to say, does not 
let light go through it. A little of it can be seen be- 
tween the eyelids, as the *' white of the eye.** The opaque 
part of the outer coat is named the sclerotic (i, Fig. 55). 

on its front ? Where does the optic nerve join it ? Where does the 
nerve go? Function of this nerve? 

5. What coats has the eyeball ? Nature of the outer. Describe the 
sclerotic. The cornea. The choroid. The iris. The pupil. Why 



THE COATS OF THE EVE, 22/ 

The front part of the outer coat is the transparent por- 
tion above mentioned. It is called the cornea (3). 

The middle coat is colored. Its hinder portion, 10, is 
black, and lies close against the sclerotic; it is called the 
choroid. Its front part separates from the outer coat, and 
instead of lying close against the cornea, turns in a little 
way behind it, 14, so as to leave a space, 30, between. 
This part of the middle coat is called the iris. Its color 
varies; we see it through the cornea, and say the eye is 
brown, or blue, or gray, or black, according to the color 
of the iris. In the middle of the iris is a hole, the pupil 
of the eye. It looks black, just as a hole opening into a 
box whose inside was painted black would, if you viewed 
it from outside, although the hole would let light into 
the box. The dark choroid answers to the black paint 
inside the box; in some animals, as dogs and cats, part 
of it is not black, and so the inside of the eyes of those 
animals, seen through the pupil, often looks shining. In 
bright light, the pupil becomes smaller, so as to protect 
the nerves inside the eye from being over-stimulated and 
dazzled: when there is not much light the pupil becomes 
larger. If you stand in front of a mirror and close your 
eyes for half a minute, and then open them and let light 
get into them, you can watch your pupils getting 
smaller. 

The inside coat of the eyeball is the retina^ 15. It is 
very thin, and is transparent so that the dark color of 
the choroid shows through it. The retina only lines the 
hinder half of the eyeball. It is the sensitive part of 

does the pupil look black ? What is said of its expansion and con- 
traction ? How can you see the contraction of your own pupil ? What 
is the retina? Describe it. Its position ? Of what does it consist ? 
Illustrate the connection of optic nerve and retina. 



228 THE CONTENTS OF THE EYEBALL, 

the eye, and consists of the spread-out fibres of the optic 
nerve, and the peculiar tips or *' end organs" joined to 
them. If you should take a cord, and fray out its threads 
at one end, and spread them out on all sides^ the cord 
would answer to the optic nerve, and the spread-out 
threads to its fibres in the retina, except that each 
thread, in order to make the resemblance greater, ought 
to have a very small rod or cone easily excited by 
light, attached to its end. 

6. The Interior of the Eyeball is filled up by liquid or 
jelly-like matters, surrounded by its coats, as the pulp 
of an orange is surrounded by the rind. These sub- 
stances are all transparent; they guide to the retina, 
light which enters the eye through the cornea and pupil. 
They are three in number, (i) The crystalline lens, 26, 
27, 28, just behind the iris. It is soft and jelly-like. (2) 
The aqueous (watery) humor, 30, a watery liquid be- 
tween the crystalline lens and the inner side of the 
cornea. (3) The vitreous (glassy) humor, 29, behind the 
crystalline lens, a soft jelly filling up all the back part of 
the cavity of the eyeball. 

7. The Use of Aqueous Humor, Lens, and Vitreous Humor 
is to gather the rays or lines of light which enter the eye, 
and so bend and direct them, that all those starting from 
one point outside the eye meet again in one point on the 
retina, and excite the same nerve-fibre. This enables us 
to see things distinctly, because an exact image of the 
thing looked at is made on the retina. In Fig. 56, O 
answers to the lens of the eye; Z>, E^ is the object looked 

6. How is the interior of the eyeball filled ? Use of these sub- 
stances ? Their number ? Names ? Describe each. 

7. What is the use of aqueous humor, vitreous humor, and lens? 
How does their action enable us to see distinctly? How is the image 



IIOPV IMAGES ARE MADE ON THE RETINA. 229 

at; and d, e, its image on the retina. The image is much 
smaller than the object, and is wrong side up, but the 
mind has learned by experience to understand it in the 
right \yay. 




Fig. 56 — Illustrating the formation behind a convex lens of a diminished and 
inverted image of an object placed in front of it. 

8. Short-Sight and Long-Sight. — When you use a tele- 
scope or an opera-glass to look at any object, you have to 
focus it. The arrangement which will enable you to 
use it for seeing near objects distinctly, must be changed 
before you can use the glass for seeing things farther 
off. In our eyes, the lens does this focusing; it changes 
according as we look at near or distant things. In per- 
sons with good eyes [A, Fig. 57), the lens can accurately 
focus on the retina, images of very distant objects, and 
also of things within seven or eight inches of the eye. 
In other persons [B), the eyeball is too long from front 
to back, and the lens cannot focus on the retina the 
rays or lines of light coming from distant objects: such 
persons are short-sighted. They can see very distinctly 
things near the eye, but more distant objects seem 

of an object looked at, depicted on the retina? Why do we see it 
rightly ? 

8. How is a telescope arranged for seeing near or distant objects ? 
How do our eyes focus what they look at ? What is said of this 
power in good eyes ? Why are some eyes short-sighted ? Why are 
others long sighted? 



230 



HYGIENE OF THE EYES. 



blurred and indistinct. The op[)osite defect is long-sight. 
In those who suffer from it, the eyeball is so flat that the 
lens cannot focus on the retina rays of liglit coming 
from a near object (C, Fig. 57). 




Fig. 57.— Diagram illustrating- the path of parallel rays of lig-ht after entering 
a healthy, well-shaped eye {A), a short-sighted eye (i5), and a long-sighted eye (C). 

9. Hygiene of the Eyes.— Looking directly at very 
bright objects, as the sun or an electric lamp, dazzles 
and injures the eyes; so does sudden change from dark- 
ness to light. On first waking, the eyes should be some- 
what gradually accustomed to bright light. The ill 
effects of such changes are much less serious than the 
harm that may be done by using the eyes when there is 
not enough light to see clearly. Frequent reading or 

9. What is the effect on the eyes of looking at very bright lights ? 
Why should they be gradually accustomed to light after sleeping? 
What is even more injurious to the eyes than sudden changes from 



E YEUDS.— TEARS. 23 1 

sewing in such feeble light that the eyes feel strained, 
will certainly injure them permanently. 

Long-sight and short-sight are not diseases. They 
are due to the fact that the eyeball is not perfectly 
shaped, but it may, nevertheless, be perfectly healthy. 
Both defects are easily remedied by proper spectacles 
or eye-glasses. If neglected, they lead not only to dis- 
ease of the eye itself, but to headaches, and other 
symptoms of nervous disorder. 

10.- The Eyelids are folds of skin moved by muscles 
so as to cover or uncover the front of the eyeball, or, as 
we ordinarily say, to shut or open the eye. Opening 
along the edge of each eyelid, are twenty or thirty small 
glands. Their secretion is greasy and keeps the tears 
from flowing over the edge of the eyelids, except when 
they are secreted in large quantity. The eyelid-secre 
tion is sometimes too abundant, and then appears as a 
yellowish matter along the edges of tlie eyelid. It often 
dries during the night and causes the lids to be glued 
together in the morning. 

11. Tears are secreted by the tear or lachrymal glands, 
which lie, one in each eye-socket, above and to the outer 
side of the eyeball. They are poured on the front of the 
eye by the tear-ducts which open on the deeper or inner 
side of the upper eyelid, near its outer corner. Tears 
are secreted all the time, but usually only in small 
quantity. Winking spreads them all over the front of 



darkness to bright light? How may short sight or long-sight be 
remedied ? What happens if they are neglected ? 

10. What are the eyelids ? What open along their edges? Use of 
these glands? Why are the eyelids sometimes glued together in the 
morning? 

11. Where are the tear-glands? Where do these ducts open? How 



232 



HEARING. 



the eyeball, and they keep it moist. What remains is 
drained off by canals which run from the inner corner 
of each eyelid to the inside of the nose, from which the 
liquid flows into the pharynx, and is swallowed. In 
weeping, the tears are secreted faster than these canals 




Fig. 58. — Semi-diagrammatic section through the rig^ht ear. J/, concha. G, ex- 
ternal auditory meatus. 7", tympanic or drum membrane. /*, Tympanum. Ex- 
tending from 7" to ^ is seen the chain of tympanic bones. R, Eustachian tube. 
F, B^ S, bony labyrinth: K, vestibule; B, semicircular canal; S, cochlea, d, /, /', 
membranous semicircular canal and vestibule. A, auditory nerve dividing into 
branches for vestibule, semicircular canal, and cochlea. 

can carry them off, so the}^ flow over the lower eyelids 
and trickle down the face. 



12. Hearing. — The ear consists of three portions, known 
as the externa/ ear^ the iniddle ear or tympanum (drum), and 
the inter7ial ear or labyrinth. The labyrinth is so named 

are they spread over the eye ? Where are they usually carried from 
the eye? Why do they trickle down the face in weeping? 

12. What are the three main portions of the ear? Why is the 



THE EAR, 233 

because it has many winding passages in it. The nerves 
of hearing are the two auditory nerves. One runs to each 
ear from the brain, and its fibres end in the labyrinth, 
in connection with peculiar very small organs which are 
easily excited by slight shaking, and then excite the 
fibres of the auditory nerve. Everything that gives out 
sound shakes or vibrates, and sets the air all round it 
shaking. The use of the outer ear and middle ear is to 
take up the vibrations of the air and pass them on to the 
organs on the ends of the nerve-fibres in the inner ear. 

13. The External Ear consists of the expansion (J/, 
Fig. 58) seen on the exterior of the head, called the con- 
cha (shell), and a passage leading in from it, the external 
auditory meatus, G. This passage is closed at its inner end 
by the tympanic, or drum, membrane, T. It is lined by a 
prolongation of the skin, through which numerous small 
glands, secreting the wax of the ear, open. 

14. The Tympanum, or drum-chamber of the ear (Fig. 
59 and P, Fig. 58), is a small cavity in one of the bones 
on the side of the skull. It is closed externally by the 
drum-membrane. From its inner side the Eustachian 
tube {R, Fig. 58) proceeds and opens into the pharynx 
(g, Fig. 30). This tube allow^s air from the throat to 
enter the tympanum, and serves to keep equal the pres- 
sure of the air on each side of the drum-membrane. 
Three small bones (Fig. 59) stretch across the tympanic 
cavity from the drum-membrane to the labyrinth; they 



labyrinth so named ? What are the auditory nerves ? What is at- 
tached to ends of their fibres in the ear? How used in helping us to 
hear ? Use of outer and middle ear ? 

13. Of what does the external ear consist? What is found at the 
inner end of its passage ? How is the passage lined ? 

14. Describe the tympanum. What is the Eustachian tube? Its 



234 THE INTERNAL EAR. 

pass on to the labyrinth, the vibrations of the membrane, 
produced by vibrations of the air. The outmost bone 
is the malleus or ha??imer'bone^ L j the inmost, the stapes 
or stirrup-bone, S j and the one between, the incus or anvil- 
bone, H. 




Fig. 59.— The tympanic cavity, C, C, and its bones, considerably magnified. G^ 
the inner end of the external auditory meatus, closed internally by the conical tym- 
panic membrane; Z,, the malleus, or hammer-bone; //, the incus, or anvil-bone; 
6", the stapes, or stirrup-bone. 

15. The Internal Ear, or Labyrinth, consists of cham- 
bers and tubes hollowed out in the inner part of the 
temporal bone, T, Fig. 6, and containing thin bags and 
tubes, filled and surrounded by watery liquid. Inside 
these bags and tubes the fibres of the auditory nerve 
end. Its middle chamber, called the vestibule ( F, Fig. 58), 
has an opening, the oval for ainen, o, in its outer side, into 

use ? Number and arrangement of the bones in the tympanum ? 
Their use ? Names and position of these bones ? 

15. Of what does the internal ear consist ? Where do the fibres of 
the auditory nerve end ? Name of the middle chamber of the internal 
ear? Where is the oval foramen, and what fits into it? Where are 



HYGIENE OF THE EAI 235 

which the inner end of the stapes, or stirrup-oone, fits. 
Behind, the vestibule opens into three semicircular canals, 
one of which is shown at B, and in front into a spirally 
coiled tube, S, the cochlea. 

When shakings or vibrations of the air make the tym- 
panic membrane vibrate, it shakes the tympanic bones; 
the stapes, vibrating in the oval foramen, then shakes 
the liquids in the labyrinth, and sets up vibrations in 
them, which excite the endings of the auditory nerve. 
The stimulated auditory nerve then conveys a nervous 
impulse to the part of the brain concerned with hearing 
and excites it, and a sensation of sound results. 

16. Hygiene of the Ear. — The outer parts of the ear 
are less tender than the eye^ and are more often injured 
by unnecessary meddling. When the ear is healthy, its 
wax dries up into scales and is shed in proper quantity. 
Some of it is necessary to protect the inner parts of the 
ear. Rubbing it out by stiff objects, not only removes 
it too fast, but may cause inflammation of the tympanic 
membrane. If the wax is clearly excessive, or if there is 
any running from the ear, it is wisest to consult a physi- 
cian at once. No stiff rod should ever be put into the 
ear, except by a skilled person. The tympanic mem- 
brane is very thin and may easily be torn. Young chil- 
dren often put such things as peas and small beans in 
their ears. If they do not come out very easily, get a 
doctor to remove them. In any such case, do not pour 

the semicircular canals ? The cochlea ? Describe how the endings of 
the auditory nerve are excited by vibrations of the air. What results 
when the auditory nerve is stimulated ? 

16. Why are the ears more often injured than the eyes by meddling ? 
What happens to the wax of the ear in health ? Why is some wax 
neccssiry? What may result from removing it? What should be 
done when there is any running from the ear ? When a chil4 has put 



236 TOUCH, 

water into the ear; it causes a pea or bean to swell, and 
makes its removal very difficult. 

Deafness may be caused in many ways: by disease of 
the auditory nerve, by disease of the labyrinth or of the 
tympanum, by stoppage of the outer passage by wax or 
some foreign object, or by inflammation and swelling of 
the membrane lining the Eustachian tubes. Swollen 
tonsils (p. 10 1). or a cold which has settled on the throat, 
or smoking, very often cause deafness in the way last 
mentioned. If the auditory nerve or the internal ear are 
at fault, the deafness may be incurable. In most other 
cases, cure is possible with medical aid. In the case of 
a cold, the cure usually occurs of itself if you have a 
little patience. 

17. Touch, or the Pressure-Sense. — Many sensory nerves 
end in the skin, and through it we get several kinds of 
sensation; touchy /leat and cold^ axid pain ; and we can with 
more or less accuracy say from what parts of the skin 
they have come. The interior of the mouth also pos- 
sesses these feelings. Through touch, we recognize pres- 
sure on the skin, and the force of the pressure; the soft- 
ness or hardness, roughness or smoothness, of the body 
producing it; and the form of this body, when if is not 
too large to be felt all over. The nerves of touch are 
very numerous. A great many of them end inside 
papillae of the dermis (p. 6^, 

18. The Delicacy of the Sense of Touch is very different 

some foreign body into its ear? Name some of the causes of deaf- 
ness. How may swollen tonsils cause deafness ? When is deafness 
apt to be incurable ? 

17. What sensations do we get from the skin ? What other part 
of the body gives rise to these sensations? What do we recognize 
through touch ? Where dg many of the nerves of touch end ? 



TEMPERA TURE^SENSE. 237 

On different parts of the skin. It includes two dis- 
tinct things, which are often confounded. In the strict 
sense of the words, touch is most delicate where the 
smallest pressure can be felt. In this meaning, the sense 
of touch is most acute on the forehead and temples, 
where a lighter weight can be felt than on any other 
part of the skin. Usually, however, by delicacy of touch 
is meant the accuracy with which, the eyes being 
closed, we can tell the exact point of the skin which is 
touched. In this meaning, the sense of touch is most 
acute on the tip of the tongue, the edge of the lips, and 
the ends of the fingers. If the blunted points of a pair 
of compasses, closed to within one twelfth of an inch, be 
gently laid, at the same moment, on a finger-tip, we dis- 
tinguish between them and feel two touches, while on 
the back of the neck they must be more than an inch 
apart before we can distinguisli them. The papillae of 
the dermis are always numerous where the distinguish- 
ing power is great. 

19. The Temperature-Sense. — By this is meant our fac- 
ulty of perceiving cold and heat; and, with the help of 
these sensations, of perceiving whether things are cold 
or hot. Its organs are the whole skin, the mucous mem- 
brane of mouth, pharynx, and gullet, and of the entry of 
the nose. Burning the skin will cause pain, but not a 
true temperature-sensation, which is quite as different 
from pain as touch is. 

18. What is meant by delicacy of touch in the strict sense of the 
words? Where is it most acute ? What is usually meant by delicacy 
of touch ? Where is it most acute ? Give an illustration of its variation 
on different regions of the skin. Where are the papillae numerous? 

19. What is the temperature sense ? What are its organs ? 



23^ SMELL AND TASTE. 

20. Smell. — The organ of smell, or the olfactory orgatl, 
consists of the mucous membrane lining the upper por- 
tions of the two nostril-cavities. Part of it is shown at 
and/, Fig. 42. The nerves of smell are the two olfac- 
tory nerves, one of which runs from each nostril-chamber 
to the brain. 

21. Odorous Substances frequently act powerfully when 
present in very small quantity. A grain or two of musk 
kept in a room will give the air in it an odor for years, 
and yet at the end will hardly have diminished in weight, 
so infinitesimal is the quantity given off from it to the 
air and able to excite the sense of smell. 

22. Taste. — The organ of taste is the mucous mem- 
brane on the upper side of the tongue, and the under 
side of the soft palate (p. loi), The mucous membrane of 
the tongue presents innumerable elevations or papillae. 
Some are organs of touch, for the tongue has the sense 
of touch as well as of taste. Others contain the endings 
of nerve-fibres which, when excited, stimulate the taste- 
centres in the brain and cause sensations of taste. 

Many so-called tastes (flavors) are really smells ; 
particles of substances which are being eaten reach the 
nose through the pharynx (see Fig. 42), and arouse smell- 
sensations which, because they accompany the presence of 
objects in the mouth, we take for tastes. Such is the case 
with most spices; when the nasal chambers are blocked 
during a cold in the head (p. 154), or closed by holding 

20. Of what does the olfactory organ consist? 

21. Illustrate the efficiency, so far as producing smell-sensations is 
concerned, of a very small quantity of an odorous substance. 

22. What is the organ of taste? What is found on the mucous 
membrane of the tongue ? What are the uses of its papillae ? 

What are many so called tastes ? Illustrate. 



DEPENDENCE OF FLAVOR ON SMELL. 



239 



the nose, the so-called " taste" of spices is not perceived 
when they are eaten. If cinnamon, e.g., is chewed under 
such circumstances, the only sensation felt is a sort of hot 




Fig. 60. — The upper surface of the tongue, 
fungiform papillae ; 4, filiform papillae. 



I, 2, circumvallate papillae; 3, 



feeling in the mouth. Some of the most nauseous medi- 
cines have really no taste, or very little. If the nose be 
held, they can be swallowed without disgust. 



CHAPTER XXII. 

THE ACTION OF ALCOHOL ON BODY, MIND, AND 
CHARACTER. 

1. Introductory. — We hope that the boys and girls for 
whom this book has been written, with its statement of 
the structure and working of the parts of the human 
body, and the rules which must be observed if health is to 
be kept, have had little chance to gain experience of the 
evils of intemperance. Unhappily, none of us can re- 
main long ignorant of them. All around us are those 
who suffer in one way or another from the effects of alco- 
holic drinks. We speak not only of those who them- 
selves indulge in them, but of the far larger number 
whose lives are spoiled by the ruin of their natural pro- 
tectors and their loved ones. 

We do not mean to say that most of those who drink 
liquor are drunkards, or indulge in it to excess, in the 
ordinary sense of the words; but when we think of the 
great number who daily take drinks containing alcohol; 
when we call to mind the fact that what is usually called 
moderate drinking, which never makes a man drunk, is 
often positively hurtful, and may alter for the worse 
nearly every important organ of the body; when we re- 

I. Why are we unlikely to remain ignorant of the evils of alcohol- 
drinking ? What is said of *' moderate" drinking? Of nervous dis- 
eases due to alcohol? Of its general effect on human happiness? 



J^ESVLTS OF INTEMPERANCE. ^4! 

member that nervous diseases are very frequently pro- 
duced by alcohol, and are more often transmitted by 
parents to their children than any other class of dis- 
eases, assuming worse forms as they are passed on from 
generation to generation; when we recall such facts, we 
have no reason to wonder that more disease and prema- 
ture death, more crime and misery, are due to alcohol 
than to bad drainage, foul air, insufficient food, unsuit- 
able clothing, or any other of the subjects treated of in 
an elementary text-book of physiology and hygiene. 

The habit of drinking is often formed in ignorance of 
its consequences. Be warned and instructed in time, to 
protect yourself and others against it. Many of the dis- 
eases produced by alcohol come on so gradually that they 
are not recognized until the will has become too weak 
to resist what the appetite craves. 

The form of disease depends on the sort of drink, the 
amount, and the constitution. Some few there are, 
whose excretory organs are so active that the alcohol is 
quickly passed out of the body, and no disease, due to 
it, manifests itself until the close of, perhaps, a long life. 
Such persons are, however, marked exceptions to the 
general rule, which may be thus stated: prolonged exces- 
sive use of alcoholic liquors^ leads surely to disease of the body 
and disease of the mind; often to insanity and death, 

2. Alcoholic Drinks, as you have already learned (p. 94), 
are all such intoxicating liquors as brandy, whiskey, gin, 
rum, wines, ales, beer, and cider ; also mixtures which 

How is the habit often formed? Why are the diseases caused by 
it often discovered too late ? On what does the form of disease de- 
pend ? Why do some persons escape for a long time ? What is the 
general rule ? 

2. Name the alcoholic drinks most often used. 



242 ALCOHOL AS FOOD. 

contain them, as cordials, punch, egg-nogs, and many 
'' tonics." 

We have studied their effects upon some of the most 
important organs of the body in turn; but in order to fix 
them more clearly in our minds, let us review the whole 
subject. 

3. Alcohol as a Food. — Foods build tissues; alcohol leads 
to overgrowth of some tissues, but not to growth of 
muscle, brain, or gland. Foods supply strength or 
working power; alcohol stimulates brain and muscle to 
overwork, and as it nourishes neither, the final result is 
failure in strength and endurance. Foods maintain 
animal heat; alcohol makes one feel warm for the mo- 
ment, but its actual effect on the temperature of the 
body is to lower it (pp. 96, 97). 

4. EflFects of Continued Use of Alcohol on Various Tis- 
sues and Organs. — These may be summed up as follows: 

Connective tissue is so increased in quantity that it 
crushes and destroys parts which, when present in only 
healthy amount, it protects (p. 14). 

The muscles have their strength, and their power of 
keeping a long time at work, lessened (p. 58). They are 
also made liable to chronic rheumatism (p. 50). 

The skifi has its vessels dilated and an excessive amount 
of blood made to flow to it, causing congestion; and im- 
pairing that activity of its glands necessary to maintain 
health (p. 76). 

The digestive organs in general are often diseased in 



3. What is said of alcohol as regards the building of tissues ? As 
a strengthener and stimulant ? In regard to its effect on the tempera- 
ture of the body ? 

4. Action of alcohol on connective tissue? On the muscles ? The 



DISEASES DUE TO ALCOUoL 243 

Consequence of the general slow poisoning of the body 
caused by alcohol. The stomach and liver are more 
directly attacked by it. 

1. The mucous membrane of the stomach becomes 
congested, then inflamed. It fails to secrete gastric juice 
and indigestion results (p. 130). 

2. The true liver-substance being injured or destroyed 
by increased growth of connective tissue, the organ 
becomes a shrunken rough mass, unfit to perform its 
important duties in the nourishment of the body 

(P- 132). 

The blood has its power of absorbing and carrying 
oxygen decreased, and also its power of clotting. Hence 
the temperature of the body and its working power are 
lessened, and any wound is more apt to bleed danger- 
ously (p. 161). 

The arteries have their walls weakened so that they be- 
come liable to burst under the pressure of the blood 
inside them (pp. 161, 162). 

The heart has its beat quickened so that it does not 
get enough rest. Its overworked muscle thus does not 
get sufficient nourishment, and at last becomes unable 
to pump the blood along (p. 162). 

The respiratory organs have their lining mucous mem- 
brane congested and irritated, increasing the liability to 
colds and other diseases (p. 184). 

The kidneys are overstimulated, and at last become 
unable to do properly their work of removing nitrogen 
wastes. Very often a fatal malady, named Bright's dis- 
ease, is produced (p. 189). 

skin ? The digestive organs in general ? The stomach ? The liver ? 
The blood? The arteries? The heart? The respiratory organs? 



244 DISEASES DUE TO ALCOHOL. 

The brain and spinal cord are kept in a chronic state of 
congestion * and overexcitement. This results at first 
in inflammatory disease (delirium tremens); later in 
paralysis, epilepsy, or insanity (pp. 212, 214). 

The senses are dulled, partly from disease of the nerves 
and nerve-centres, partly by diseased changes in the 
sense-organs. 

No tippler probably ever suffered from all of the dis- 
eases above mentioned, and most of them may develop 
in persons who are total abstainers, but some of them 
are pretty sure to develop in habitual drinkers, and they 
are all more frequently due to intemperance than to 
any other single cause. It is also well known that in 
any serious disease, the chances of recovery are smaller 
in the case of drinkers. 

5. Continued Alcoholic Indulgence Causes Premature Old 
Age. — Many of the alterations in various tissues and or- 
gans above described as brought about by alcohol, are 
very like the changes which naturally occur in old age. 
When alcohol does not cause some actual disease, as 
Bright's disease, or delirium tremens, it often hastens 
the ageing of the body. The organs lose strength and 
activity, and become old before their time. 

The kidneys ? The brain and spinal cord? The senses ? How does 
habitual drinking affect the chances of recovery from disease ? 

5. What does alcohol often do when it does not cause actual dis- 
ease ? 



* " I once had the unusual though unhappy opportunity of observing the same 
phenomenon in the brain-structure of a man who, in a fit of alcoholic excitement, 
decapitated himself under the wheel of a railway-carriage, and whose brain was 
instantaneously evolved from the skull by the crash. The brain itself, entire, was 
before me within three minutes after death. It exhaled the odor of spirit most 
distinctly, and its membranes and minute structures were vascular in the extreme. 
It looked as if it had been recently injected with vermilion." — Dr. B. W. Rich- 

AKDSON. 



CHARACTER DESTROYED BY INTEMPERANCE. 245 

6. The Destruction of Will and Character by Alcohol. — 

One of the first effects produced by alcoholic drinks 
is weakening of the control of the will over the actions. 
A slightly tipsy man laughs and talks loudly, says and 
does rash things, is enraged or delighted without due 
cause. If the amount of alcohol be increased, the 
power of the will is further lessened. The muscles 
obey it very imperfectly, so speech becomes indistinct 
and the legs unsteady. At the same time, the reason 
is so weakened that the man is the prey of every tran- 
sient whim: he is, by turns, affectionate and cruel, dar- 
ing and craven, buoyed by hope and crushed by despair, 
arrogant and full of shame, with no sufficient cause. 
Habitual excessive use of alcohol thus soon leads to a 
state in which the emotions are permanently overexcited, 
and the will enfeebled. The man's highly emotional 
state exposes him to special temptations, to excess of all 
kinds of passion, and his weakened will decreases his 
power of resistance. The final result is a degraded moral 
condition. He who was prompt in the performance of 
duty begins to shirk that which is irksome; energy gives 
place to indifference, truthfulness to lying, integrity to 
dishonesty, for even with the best intentions in making 
promises or pledges, there is no strength of will to keep 
them ; the man at last becomes regardless of every duty, 
and even unable to accomplish any which momentary 
shame may make him desire to perform. 



6. Point out one of the first effects of alcoholic drinks. How il- 
lustrated ? If the amount is increased, what happens ? Illustrate 
from the muscles? How is the weakening of the reason in a drunken 
man exhibited? To what does habitual excessive use of alcohol lead ? 
What are the consequences ? The final result ? What is the only 
liope for an habitual drunkard 1 



246 CONFINEMENT OF INEBRLATES. 

For such a one there is but one hope — confinement in 
an asyhim where, if not too late, the diseased craving 
for drink may be gradually overcome, the prostrated 
v^ill regain its ascendency, and the man at last gain the 
victory over the brtcte. 



GLOSSARY. 



Ab~dd*men{Lai.abdere\ to conceal, ^7/«^«^«w, entrails). The cavity containing the 
stomach, liver, intestines, kidneys, etc. 

Ab-sorp'tioH {Lat. absorbere^ to swallow, or take in). The taking up of nutritive 
or waste matters by the blood-vessels or lymphatics. 

Al-bu'men{Lat. from albus^ white). The name of a group of nourishing sub- 
stances containing nitrogen, which resemble in nature the white of an ^%%. 

Al-i-ment'a-ry {Lat. alimentarius^ from aUre^lo nourish). Pertaining to the 
nourishment of the body. 

A-ndt' o-my {Gr. anatemnein^ to cut up). The science which deals with the struc- 
ture of living things. 

An'en-rism {Gr. aneurisma^ a widening). A swelling or tumor due to unhealthy 
dilatation of an artery. 

A'or'ta {Lat.). The great artery arising from the left ventricle of the heart. 

A'que-ous {Lat. aqua^ water). Like water. 

Ar'ter-y {Gr. arteria^ the windpipe). The name given to vessels which carry 
blood from the heart ; these vessels were supposed by the old anatomists to con- 
vey only air, hence the name. 

Ar-tlc'u-lar {Lat. articularius). Pertaining to a joint. 

Ar-ttc-u-la'iion {Lat. articulatio). The joining of bones in the skeleton. 

Au'ri-ele {Lat. auricula., a little ear). The name given to the chambers at the 
base of the heart, which receive blood from the veins, because they have pro- 
jections which resemble in form the ears of some quadrupeds. 

Au'dt-to-ry {Lat. audire^ to hear). Pertaining to the sense of hearing. 

Bi'cej>s {Lat. having two heads). The name given to muscles which split at one 

end, so as to have there two separate attachments to the skeleton. 
Bi-cHs'pid {Lat. bis^ twice, cuspis, a point). The name of teeth which have two 

points on the crown. 
Brdn'chi-al{s^G Bronchus). The name of the branches of the windpipe inside 

the lungs. 
Bron-chi'tis. Inflammation of the bronchial tubes ; a cold " on the chest." 
Brdn'chus {Gr. bronchos^ the windpipe). The name of the two branches into 

which the windpipe divides in order to reach each lung. 

Ca-nine' {Lat. caninus, pertaining to dogs). The pointed teeth, on each side of 

the incisors, which are very large in dogs. 
Cdj>'il-la-ry {Lat. capillus^ hair). The name given to the smallest blood-vessels, 

because they are so slender. 
Car'di-ac (Gr. kardta, the heart; also the stomach). The name of the opening of 

the gullet into the stomach; it lies near the heart. 
Car' pal {Gr. karoos, the wrist). The name given to the wrist-bones. 



248 GLOSSARY. 

Car'ti-lage {Lai. cariilago). The technical name of gristle; an elastic flexible ma- 
terial found in the skeleton. 

Cd'se-lne {Lat. caseus^ cheese). An albumen found in milk. When milk turns 
sour the caseine curdles, and when the whey is squeezed out of the curd, it re- 
mains as cheese. 

Cell {Lat. cella, a room or cellar). The name of the tiny microscopic elements 
which, with slender threads or fibres, make up most of the body: they were once 
believed to be little hollow chambers, hence the name. Most animal cells are 
not hollow. 

Cem'-ent. The substance which forms the outer part of the fang of a tooth. 

Cer-e-bel' lum {Lat. dim. of cerebrum^ brain). The hinder and lower division of 
the brain. The small brain. 

Cer'e-bro spi'nal. Pertaining to the brain and spinal cord. 

Cer' e-brum {Lat.). The chief division of the brain. The large brain. 

Cho'roid {Gr. chorion^ a membrane, and eidos^ form). The middle membrane or 
coat of the eyeball. 

Chyle {Gr. ckulos, juice). The digested nutritious part of the food prepared in and 
absorbed from the intestines. 

Chyme {Gr. chunios). The name of the partly digested food which passes from 
the stomach to the intestine. 

Cldv'i-cle {Lat. clavicula, a small key). The collar-bone: so named because it 
somewhat resembles in form an ancient key. 

Co-dg-uld' Hon {Lat. coagulatid). The act of turning from a liquid to a semi- 
solid state. The clotting of blood. 

Coc' cyx {Gr. kokkujc, a cuckoo). The lowest bone of the spinal column, named 
from a fancied resemblance in form to the bill of a cuckoo. 

Coch'le-a {Lat. cochlea., a screw). A coiled or twisted portion of the internal ear. 

Con'cha {Lat. a shell). The portion of the ear which projects from the side of the 
head. 

Con-ges'tion{Lat. congestion the act of gathering into a heap). An unhealthy ac- 
cumulation of blood in any part of the body. 

Con-nect'ive tissue. A tough stringy material used for binding together the parts 
of the body. 

Cofi-j'unc' ti-va {Lat. conjunctivus., serving to unite). The name of the thin mem- 
brane which lines the inner side of the eyelids and covers the front of the eye- 
balls. 

Con-trac'tion {Lat. contraction a drawing together). The shortening of muscles 
when they work. 

Con-vo-lu'tion {Lat. convolutus^ twisted together). The winding ridges on the 
surface of the brain. 

Cor'ne-a {Lat. corneus^ horny). The transparent membrane in front of the eye. 

Cor'pus-cle {Lat. corpusculumy dim. of corpus^ body). The name given to ilie 
minute particles which float in the blood-liquid. 

Cr^s'tal-line {Gr. krustallinosn ice-like, or resembling transparent crystal). TJie 
name of the lens of the eye. 

Cu'ti-cle {Lat. cuticulus^ dim. of cutis^ skin). The outer layer of the skin; the epi- 
dermis. 

De-gen-er-d'ti^n {Lat. degenerare^ to grow worse; to deteriorate). A change in 
the structure of any organ which makes it less fit to perform its duty or func- 
tion. 

Deg-lu-ti'tion {Lat. deglutire, to swallow down). The act or process of swallowing. 

Den' tine {Lat. dentis, of d^ tooth). The hard substance which forms most of a 
tooth. Ivory, 



GLOSSARY. 249 

Der'mis {Gr. derma^ the skin or hide). The deeper layer of the skin, containing 
blood-vessels, 

DV a-phragin (Gr. dia/>hragma^ a partition-wall). The muscular membrane which 
separates the cavity of the chest from that of the abdomen. 

Di-ar-rhce' a {Gr. diarrein, to flow through) An unnaturally frequent and liquid 
evacuation of the bowels. 

Di-ges'tion {Laf. digestio, the distribution of food through the body). The pro- 
cess of preparing the nutritious parts of the food for absorption from the ali- 
mentary canal. 

Dls-lO'Cd'tion {Lat. dislocare^ to put out of place). The name of an injury to a 
joint, in which the bones are forced out of their sockets. 

Dor' sal {Lat. dorsum^ the back). Pertaining to the back of the body. 

Diict {Lat. ductus., a leading or drawing). A tube by which fluid is conveyed 
from a gland. 

Dys-peP'si-a {Gr. dus^ ill, pessein^ to digest). A condition of the alimentary canal 
in which it digests imperfectly. Indigestion. 

En-dm'el. The smooth hard substance which covers that part of a tooth which 

projects beyond the gum. 
Ep-i-dervi' is [Gr. epi^ upon, derma., skin). The outer layer of the skin. The 

cuticle. 
Ep-i-glot' tis {Gr. epi, upon, glotta, tongue). A cartilage at the root of the tongue 

which closes the opening from the throat to the larynx during swallowing. 
Ep'i-lep-sy {Gr. epiUipsis., a failure or lack). A nervous disease accompanied by 

fits in which consciousness is lost. The falling sickness. 
Eil-std' chi-an (from an Italian anatomist named Eustachi). The tube which leads 

from the throat to the middle ear or tympanum. 
Ex-cre'tion {Lat. excretus, sifted out). The act of removing waste matters from 

the body. Also any such waste matter. 
Ex-pi-rd'tion {Lat. expiro, I emit, or breathe out). The act of expelling air from 

the lungs. 

Fau'ces {Lat.) The part of the mouth which opens into the pharynx. 

Fe'niur {Lat.) The thigh-bone. 

Fi'bre {Lat. Jibra, a filament). One of the slender threads of which many parts of 

the body are composed. 
Fi'brine. The solid substance which forms in blood when it clots. 
Fib'ic-la {Lat. a clasp or buckle). The outer or small bone of the leg, running from 

knee to ankle. 
Fol'li'cle {Lat. folliculus., a small bag). A little cavity or pit. 
Fo-rd'men {Lat.) A hole or aperture. 
Ficnc'tion {Lat. functio, a performing or executing). The special action or duty of 

any organ of the body. 
Front' al {Lat. frons^ 'Os\Qiox€t\^2idi). The bone which supports the forehead and 

closes the front of the skull-chamber. 

Gdn'gli-on {Gr. a swelling). One of the smaller nerve-centres. 

Gds'tric {Gr. gaster, the belly). Belonging to the stomach. 

Gland. An organ which forms or separates from the blood some peculiar liquid, 

either for use in the body (secretion), or for removal from it (excretion). 
Glot'tis {Gr. glotta, the tongue). The narrow opening between the vocal cords. 

Hem'or-rhas^e (Gr. haima, blood; regnunai., to burst). Bleeding. 
He-pdt'ic {Gr. hepatikos). Pertaining to the liver. 



250 GLOSSARY. 

Huvie-rus {Lat.) The bone of the arm between shoulder and elbow. 

Hu'mor {Lat. moisture). The transparent hquid or semifluid substances within 

the eyeball. 
Hy'gi-ene (Gr. Hygeia, the goddess of health). That department of knowledge 

which deals with the preservation of health. 
Hy'oid {Gr. the letter «, and cidos, form). U-shaped. The name of the bone at 

the root of the tongue. 

In-ci'sor {Lat. incidere, to cut into). The name of the front teeth. 

In-spi-rd'tioti {Lat. insj>irare, to blow or breathe in or upon). The act of drawing 

a breath. 
I7i-tes'tlnes {Lat. intestinus^ inward). The coiled tube conveying food from the 

stomach. The bowels. 
In-ver'te-brate. Term applied to animals having no back-bone. 
In-voVun-tary {Lat. in., not; voluntarius., acting on free choice). » Performed 

without direction from the will; often against the will. 
I'ris {Lat. the rainbow). The colored part of the eye surrounding the pupil. 

Ju'gii-lar {Lai. juguluvi. the hollow part of the neck above the collar-bone). 
The name of the chief veins of the neck. 

Lab' y-rinth {Gr. labyrinthos, a place full of intricate winding passages). The 
name of the inner portion of the ear. 

Lack' ry -771 al {Lat. Iacri77ia., a tear). Pertaining to or conveying tears. 

Ldc'te-al {Lat. lacteus^ milky). The name of the lymphatics or absorbents of the 
small intestine. During digestion they are filled with milky-looking chyle. 

Ldr'ynx {Gr.) The portion of the air-passage, above the windpipe, in which 
voice is produced. 

Lig' a-77te7tt {Lat. Iigame7itu77i). One of the cords or bands used to bind bones 
together at joints. 

Lu77i-bd'go {Lat. Iu77tbus, a loin). A painful rheumatic disease of the muscles of 
the small of the back, 

Ly77iph {Lat. Iy77ipha., water), A colorless liquid which exudes from the blood- 
vessels and bathes the tissues and organs. 

Lyi7i-phdt'ic. The name of the vessels which contain lymph. The absorbents. 

Md'lar {Lat. viala, the cheek). The name of the cheek-bone. 

Mdl'le-us {Lat. hammer). The name of the outermost bone within the middle ear. 

2Md77i-i7tdl'i-a {Lat. ma77i77ia, 3. hrtSiSi). The name given to the highest division 

of back-boned animals, because their females suckle the young. 
Mds-ti-cd'ti07i {Lat. 77tasticatio). The act of chewing. 
Max-il'la {Lat. the jaw). The name of the jaw-bones, upper and lower. 
Me-d'tus {Lat. a going or course), A passage or channel, as the external auditory 

meatus ^vhich leads from the outer to the middle part of the ear, 
Me-dfd'la ob-lo7i-gd'ta {Lat. the prolonged or continued marrow). The continua- 
tion of the spinal cord {77iediclla spi/ialis) or marrow, which enters the skull. 
Me/n'brdne {Lat. i!ig7nbra72a, the thin skin covering the members or limbs). A 

thin sheet of tissue used to wrap and protect various organs, or to line cavities 

in the bod}\ 
Met-a-cdr'pal {Gr. meta, beyond; karpos, the wrist). The name of the bones 

between the wrist and the fingers. 
Met-a-tdr' sal {Gr. from 77ieta^ beyond, and tarsal., which see). The name of ihe 

bones in the front part of the sole of the foot. 



GLOSSARY. 251 

Mi'tral {Lat. tnitra^ a head-band). The name of the valve between the left 
auricle and ventricle of the heart, which has two flaps, like the mitre of a 
bishop. 

Mo'lar {Lat. mola, a well). The name of the grinding-teeth. 

Md'tor {Lat. viovere^ to move). Concerned in producing movement. 

Mur'cus {Lat. tnuctis, the secretion of the nose). A viscid liquid secreted by cer- 
tain membranes within the body, named mucous membranes. 

Nar-cdt'ic {Gr. narkotikos^ from narke, numbness). Any substance which dulls 
the sensibility of the nerves, and in larger doses produces unnatural sleep, 

Nd'sal {Lat. nasus, the nose). Pertaining to the nose; the name of the bones 
which support the bridge of the nose. 

0-ddn'toid{Gr. odontos^ of a tooth; eidos^ shape). The name of the bony peg of 
the second vertebra, around which the first turns. 

(E-soph' a-^^iis {Gr. oesophagos). The gullet. The tube which conveys food from 
the throat to the stomach. 

Ol-fdc'to-ry {Lat. olfacere., to smell). Pertaining to the sense of smell. 

^p'tic. Pertaining or related to the sense of sight. 

Or'gan {Lat. organum., an instrument or implement). A portion of the body hav- 
ing some special function or duty. 

Pdl-pi-td' tion {Lat. paipttatio^ a frequent or throbbing motfon}. A violent and 
irregular beating of the heart. 

Pdn'cre-as {Gr. pan., all; kreas, flesh). One of the most important glands which 
aid in the digestion of food. It is placed in the abdomen, just below the stomach, 
and pours its secretion into the upper end of the small intestine. 

Pa-pil'la {Lat. a nipple or teat). The name of the small elevations found on the 
skin and mucous membranes. 

Pa-rdl'y-sis {Gr. par aluein, to stt free or separate). Loss of function, especially 
of motion or feeling. Palsy. 

Pa-ri'e-tal {Lat. paries^ the wall of a house). The name of the bones on the top 
of the skull. 

Pa-tel'la {Lat.). The knee-cap or knee-pan. 

Pel' vis {Lat. a basin). The bony ring, made of sacrum, coccyx, and the two hip- 
bones, which surrounds the lower part of the abdomen. 

Per-i-cdr' di-um {Gr. peri, around; kardia^ the heart;. The membranous sac which 
encloses the heart. 

Per-i-os' te-uvt {Gr. peri., around; osteon., a bone). A fibrous membrane which sur- 
rounds the bones. 

Pha-ldn' ges {Gr. phalanx., a body of soldiers closely arranged in ranks and files). 
The bones of the fingers and toes. 

Pkdr'ynx {Gr. the throat). The cavity into which the nose and mouth open, and 
from which the gullet proceeds. 

Phys-i-ol'o-gy {Gr. physis, nature; logos, a discourse). The science which treats of 
the functions or uses of the different parts of animals and plants. 

Plds'ma {Gr. anything formed or moulded). The liquid part of the blood. 

Pul'mo-na-ry {Lat. puhnonis, of a lung). Pertaining to the lungs. 

Py-lo'rus {Gr.pyloros., a door-keeper). The opening from the stomach into the 
small intestine. 

Rd'di-iis {Lat.). The outer of the two bones running from the elbow to the wrist. 
Re' flex {Lat. reflexus, turned back). The name given to involuntary movements 

produced by an excitation travelling along a sensory to a centre, where it is 

turned back or reflected along motor nerves. 



252 GLOSSARY, 

Re'nal{Lai. renes^ the kidneys). Pertaining to the kidneys. 

Ret'in-a {Lat. reie, a net). The transparent nervous membrane which forms the 
inner coat of the eyeball. 

Sd'crum {Lat, sacred). The large bone near the lower end of the spine, having 

the hip-bones attached to its sides. 
Sa-li'va {Lai.). The Hquid which moistens the mouth, and aids in swallowing and 

digesting. 
Sa-j)he'nous {Gr. saphenes^ manifest). The name of a large vein which lies just 

under the skin of the leg. 
Scdfu-la {Lat.) The shoulder-blade. 

Scle-rdt'ic {Gr. skleros, hard, tough). The tough outer coat of the eyeball. 
Se-bd'ceous {Lat. sebum^ tallow). The name of the oil-glands of the skin. 
Se-cre'tion {Lat. secretin, a separating). The preparation from the blood, by 

glands, of peculiar liquids. 
Sem-.i-lu'nariLat. semi., half; luna., mooned). Shaped like a half-moon. 
Sen-sd'tion {Lat. sensus^ feeling). Any kind of feeling, as hunger or hearing. 
Se-rum {Lat. whey). The liquid part which separates from the clot, when blood 

coagulates. 
SkePe-ton {Gr. dried up). The bones and other supporting parts of the body, as 

gristles and connective tissue. 
Sfhe'noid {Gr. sphen^ a wedge; eidos., form). The name of one of the bones on the 

under side of the skull. 
St d' pes {Lat. a stirrup). The name of the innermost bone of the middle ear, which 

has the form of a stirrup. 
Ster'num {Gr. sternon, the chest). The breast-bone. 
Stim' u-lant {Lat. stimulare., to goad or stir up). Any substance which excites 

some organ of the body to do extra work, without proportionately nourishing it. 
Su-dor-ip' a-roics {Lat. sudor ^ sweat; parare., to prepare). The name of the glands 

of the skin which secrete sweat or perspiration. 
Sut'ure {Lat. sutura, a seam). The union of certain bones of the skull by the 

interlocking of jagged edges. 
Syn-ov'i-al {Gr. syn, with; oon^ an Qgg). The liquid which lubricates the joints : 

joint-oil. So called from its resemblance to the white of a raw egg. 

Tar' sal {Gr. tarsos^ a broad, fiat surface, hence the sole of the foot). The name of 
the bones below the ankle-joint. 

Tem'po-ral {Lat. tempora, the temples). The name of the skull-bones which sup- 
port the temples, and contain the inner parts of the ear. 

Ten' don {Lat. tendere^ to stretch). The cords which attach muscles to bones. 

Tho'rax {Gr. a breast-plate). The chest. The upper part of the trunk of the 
body. 

Tib-i-a {Lat.) The shin-bone. 

Tis'sue {Lat. texere, to weave). The name given to each of the materials used in 
the construction of the body, as muscular tissue, nervous tissue, bony tissue, 
etc. 

Trd'che-a {Gr, trachus, rough). The windpipe. 

Trt-cus'pid {Lat. tris^ three times; cuspis, a point). Having three points. The 
name of the valve between the right auricle and ventricle of the heart. 

Tjfm'pa-nfim {Lat. a drum). The middle or drum chamber of the ear. 

Ul'na {Lat.). One of the two bones passing from elbow to wrist. It lies on the 
inner or little-finger side. 



GLOssAkV, ^53 

V^vu-la {Lai. a little grape). The fleshy conical body which hangS down from the 
lower border of the soft palate. 

Vdr'icdse {Lai. varix). The term applied to an unhealthily distended vein. 
Vds'cii-lar {Lai. vasculiitn^ a little vessel). Pertaining to or possessing blood- or 

lymph-vessels. 
Ven'iral {Lai. venter, the belly). Pertaining to the front or belly side of the body. 
Ven'iri-cle {Lai. ventricuhis, the belly). A small cavity, as the ventricles of the 

heart. Also applied to cavities within the brain. 
Ver-ie'bra {Lai. from veriere, to turn). The name of each of the bones of the 

spinal column. 
Ves'ii-bule {Lai. a fore-court or entry to a house). A part of the inner ear from 

which the other parts open. 
Vil'lus (pi. vil'U: Lai. shaggy hair). The name of the minute hair-like projections 

of the mucous membrane of the small intestine. 
Vli're-ous {Lai. viireus^ glassy). One of the substances within the eyeball, which 

guide rays of light to the retina. 
Vdl'un-ia-ry {Lai. voluntarius). Applied to actions performed in obedience to the 

will. 



INDEX. 



Abdomen, 6 

Absorbents, or lympathic vessels, 
119 

Absorption, 99; by the lympha- 
tics, 119; from the intestine, 
118; from the stomach, 120 

Air, how changed by breathing, 
163; how purified, 166; results 
of breathing foul, 178 

Air-cells, 171 

Air-passages, 168 

Albumen, 84 

Alcohol, as food, 95, 241; as 
medicine, 97; as narcotic, 213, 
216; as stimulant, 94; cause of 
insanity. 214; of premature old 
age, 244; of various nervous 
diseases, 214; effects of, on 
arteries, 161; on the blood, 161; 
on character, 245 ; on connective 
tissue, 14, 132, 1S9; on diges- 
tive organs, 130; on the heart, 
162; on the joints, 49; on the 
kidneys, 189; on the mind, 213; 
on the muscles, 58; on the 
nervous system, 212; on re- 
spiratory organs, 184; on the 
senses, 213, 244; on the skin, 
76; on the temperature of the 
body, 96; on the will, 245; 
hereditary diseases due to, 214; 
summary concerning the action 
of alcohol on mind and body, 
240 

Alcoholic stimulants. 94 

Alimentary canal, 99 

Anatomy, 2, 10 

Aneurism, 162 



Animal matter, 10; of bone, 27; 

starch, 132 
Animal heat, 76, 82; influence 

of alcohol on, 96 
Anvil-bone, 234 
Aorta, 141 
Apoplexy, 205 
Aqueous humor, 228 
Arch of the instep, 29 
Arm, bones of, 20; muscles of, 

40 
Artery, 134; action of alcohol on, 

161; pulmonary, 141; wounds 

of, 159 
Arterial blood, 134 
Articulations, 35 
Atlas vertebra, 38 
Attention, 212 
Auditory organ (ear), 232; nerves, 

233 
Auricles, 140 
Axis vertebra, 38 

Back-bone, 5, 16 

Bad ventilation, 181 

Ball-and socket joints, 37 

Bathing, 72 

Beans, 87 

Beat of heart, 141 

Beef, 84 

Biceps-muscle of arm, 41 

Bicuspid tooth, 102; valve, 142 

Bile, 116 

Bladder, 185 

Blister, 60 

Blood, 134, 147; action of alcohol 
on, 161; changed by brea-thlng, 
147, 163; corpuscles of, 135 



256 



INDEX. 



Blood-vessels, 133; action of al- 
cohol on, 161 

Blushing, 63, 153 

Boots, effects of wearing ill- 
shaped, 30 

Bones, composition of, 26; car- 
pal, 21; fracture of, 33; hy- 
giene of, 28; hyoid, 22; meta- 
carpal, 21; metatarsal, 21; of 
arm, 20: of back, 16; of fingers, 
21; of hand, 20; of hip, 21; of 
skull, 19; of trunk, 18; of wrist, 
21; structure of, 24; tarsal, 21; 
uses of, 12 

Bony skeleton, 14; table of, 22 

Brain, 195; controls the muscles, 
44; exercise of, 208; feeling 
depends on, 199, 224; rest of, 
207, 210 

Brain and mind connected, 201 

Bread, 84, 87 

Breast-bone, 18 

Breathing, 163; through the 
mouth, 183 

Bright's disease, 189 

Bromides, 220 

Bronchi, 170 

Bronchial tubes, 170 

Bronchitis, 154 

Burns, 76 

Butter, 86 

Capillaries, 134, 146 

Carbonic acid, 164 

Carpal bones, 21 

Cartilage, 12, 13; in joints, 36, 37 

Caseine, 86 

Cavity, abdominal, 6; dorsal, 5. 

8, 10, 16; ventral, 5, 10 
Centres, nervous, 193 
Cerebellum, 194, 199 
Cerebral hemispheres, 195 
Cerebro-spinal centre, 194 
Cerebrum, 194, 199, 201 
Cheese, 86 
Chemistry, of the body, 9; of 

bones, 26 
Chest, 6, expanded by exercise, 

183; injured by tight lacing, 3?, 

182 
Chewing, 108 
Chilblains, 156 



Chloral, 219 

Choroid, 227 

Chyle, 117 

Chyme, 117 

Cigarettes, 222 

Circulation, 133, 143; effect of 
muscular exercise on, 55, 156; 
hygiene of, 153; pulmonary and 
systemic, 144 

Clavicle, 20 

Cleanliness, 71 

Clothing, 79 

Clotting of blood, 138 

Coagulation, 138 

Coccyx, 16 

Cochlea, 235 

Coffee, 93 

Colds, as cause of digestive trou- 
bles, 129; of kidney-disease, 
188; of lung-disease, 154; how 
to avoid, 153 

Cold baths, 72 

Collar-bone, 20 

Complexion, 62 

Concha, 233 

Congestion, 130, 153 

Connective tissue, 12, 13, 14; ef- 
fects of alcohol on, 14, 132, 189 

Contraction of muscles, 35, 39, 41 

Convolutions of brain, 195 

Convulsions, 42, 197 

Cooking, 89 

Corn, 87. 

Cornea, 227 

Corpuscles of blood, 135 

Cosmetics, 75 

Coughing, 17.4 

Cranial nerves, 195 

Crystalline lens, 228 

Curvature of the spine, 29 

Cuticle, 59 

Cutis, see Dermis 

Cuts, 158 

Deafness. 236 

Degeneration, fatty, 58,162 

Deglutition, no 

Delirium tremens. 2r3 

Demonstration, on blood, 148; 
on circulatory organs, 149; on 
digestive organs, 121; on joints, 
47; on muscles, 47; on renal 



INDEX. 



25? 



Demonstration — Contimicd. 

organs, 1S9; on respiratory or- 
gans, 175 

Dermis, 59, 63 

Diaphragm, 6, 172 

Diarrhoea, 129 

Diet, mixed, 127 

Digestion, 98; in mouth, 107; in 
small intestine, 117; in stom- 
ach, 113, 114 

Dipsomania, 214 

Dislocations, 48, 49 

Dorsal cavity, 5, 8, 10, 16 

Draughts, effects of exposure to, 
129 

Drum of ear, 233 

Duct, 66; bile, 116; thoracic, 119 

Dyspepsia, 124 

Ear, 232; hygiene of, 235 

Education, 210 

Eggs, 87 

Enamel, 104 

Epidemics, 59 

Epiglottis, III, 168 

Epilepsy, 205, 214 

Eustachian tube, 233 

Eye, 225; hygiene of, 230 

Eyelids, 231; secretion of, 231 

Excretion, j66 

Excretory organs compared, 187 

Exercise, effect on the chest, 

183; on the circulation, 55, 156; 

mental, 208; muscular, 52 
Expiration, 171 
External ear, 233 

Fainting, 204 

Fatty degeneration, 58, 162 

Fauces, loi 

Feeling. 199, 223 

Femur, 21 

Fever, 67 

Fibres, 14; of connective tissue, 

14; motor and sensory, 196; of 

nerves, 196 
Fibrin, 138 
Fibula, 21 
Fish, as food, 86 
Fits. 204 
Flavors, 238 
Floating ribs, 18 



Foods, 81, 83; digested in mouth, 
107; in small intestine, 117; 
in stomach, 113, 114; proper 
amount of, 126 

Food-stuffs, 84 

Foramen, oval, 234 

Foul air, 178 

Fractures, 33 

Fruits, 87 

Function, 4, 10; of back-bone, 17; 
of blood, 133; of blood-vessels, 
134; of bones, 13; of capilla- 
ries, 147; of cartilage, 13, 37; 
of cerebellum, 199; of cere- 
brum, 199, 201; of connective 
tissue, 13; of contents of eye- 
ball, 228; of heart, 134; of in- 
step, 29; of lacteals, 119; of 
large intestine, 119; of kid- 
neys, 185, 187; of liver, 116, 
132; of lungs, 171, 187; of me- 
dulla oblongata, 198, 199; of 
muscles, 35, 39, 43; of nervous 
system, 190; of pancreas, 117; 
of red blood-corpuscles, 137; of 
parts of the ear, 235; of sali- 
vary glands, 106; of skin, 59, 
187, 236; of small intestine, 
117; of stomach, 113; of sweat- 
glands, 67, 78; of tongue, 105, 
238; of valves of heart, 142; of 
valves of veins, 156 

Furred tongue, 105 

Gall, 116 

Ganglia, 201 

Garters, 156 

Gastric juice, 113 

Gelatin, 27, 88 

Glands, 65; lachrymal, 231; of 

eyelids, 231; of intestine, 116; 

of stomach, 113; salivary, 106; 

sebaceous or oil, 66; sweat or 

sudoriparous, 66 
Glottis, 169 
Gluten, 87 
Gout, 49 
Gristle, 12, 13 
Growth, 81 
Gullet, no. Ill 

Habits, 45 



258 



INDEX. 



Hair-dyes, 75 

Hairs, 64 

Hammer- bone, 234 

Hearing, 232 

Heart, 140; action of alcohol on, 
162; effect of exercise on, 156 

Health, why we should try to 
keep it, i (see also Hygiene) 

Heat, animal, 7^, 82 

High heeled boots, 30 

Hinge-joints, 37 

Hip-bones, 21 

Hip-joint, 36 

Hollow veins, 141 

Humerus, 20, 24 

Humors of the eye, 228 

Hygiene, 3; of bones, 28; of cir- 
culatory organs, 153; of diges- 
tive organs, 123; of ear, 235; 
of eye, 230; of joints, 48; of 
kidneys, 188; of mind, 208; of 
muscles, 51; of nervous sys- 
tem, 203; of respiration, 176; 
of skeleton, 28; of skin, 71; of 
teeth, 104 

Hyoid bone, 22 

Hysterics, 205 

Incus, 234 
Indigestion, 124 
Inorganic food-stuffs, 85 
Insanity, 214 
Insomnia, 208 
Inspiration, 171 
Instep, 29 
Internal ear, 234 
Intestines, 115, 119; absorption 
from, 118, 119; digestion in, 

117 
Invertebrate animals, 8, 11 
Involuntary muscles, 42 
Iris, 227 
Iron, as food, 85 

Jelly, 88 
Joint-oil, 36 

Joints, 35, 36; demonstration of, 
47; hygiene of, 49; injuries of, 

48 

Kidneys, 185, 187; action of al- 
cohol on, i8g; hygiene of, 1S8 



Knee-pan, 21 

Labyrinth, 234 

Lachrymal (or tear) glands, 231 

Lacteals, 119 

Large intestine, 119 

Larynx, 168 

Lean of meat, 35 

Ligaments, 14, 37 

Liver, 116, 132; action of alcohol 
on, 131 

Long-sight, 230, 231 

Lumbago, 50 

Lungs, 171, 188; action of alco- 
hol on, 184 

Lymph, 119 

Lymphatics, or lymph-vessels, or 
absorbents, 119 

Maize, 87 

Malleus, 234 

Mammalia, 9, 11 

Mammary glands, 9 

Man as a vertebrate animal, 8 

Marrow, of bone, 24; spinal, see 
spinal cord 

Mastication, 108 

Materials used in building the 
body, 4, 10 

Meats, 86 

Medulla oblongata, 195; func- 
tions of, 198, 199 

Membranes, 14; mucous, 100; 
tympanic, 233 

Metacarpal bones, 21 

Metatarsal bones, 21 

Milk, 86 

Mind and brain, 201 

Mineral matters, 10; of bone. 27: 
of food (inorganic food-stuffs), 

85 

Mitral valve, 142 
Morphia, 218 
Motor nerve-fibres, 196 
Mouth, 100 
Mouth-breathing, 184 
Movements, reflex, 197 
Mucous membrane, 100 
Mucus, 106 
Mumps, 106 

Muscles, 35, 39; action of alco- 
hol on, 58; contraction of,, 35, 



INDEX. 



259 



Muscles — Contintied. 

39, 41; controlled by nerves, 
42; controlled by brain, 44; 
demonstration of, 47 ; func- 
tions of, 35, 39, 43; hygiene of, 
51; involuntary, 42; not attach- 
ed to skeleton, 42; of standing, 
46; of stomach, 114; parts of, 
40 

Nails, 64 

Narcotics, 216 

Nerve-centres, 193 

Nerves, 193: action of, on mus- 
cles, 42, 197; cranial and spi- 
nal, 195; of hearing, 233; of 
sight, 226; of smell, 238; of 
touch, 236; structure of, 196; 
sympathetic, 200 

Nervous diseases, 204 

Nervous system, 190, 193; action 
of alcohol, 212; action of narco- 
tics on. 216; injured by worry, 
206; -sympathetic, 200 

Neuralgia, 206 

Nitrogen, 85 

Odontoid process, 38 

Odorous substances, 238 

CEsophagus, no, in 

Olfactory organ, 238 

Oil-glands of skin, 67 

Opium, 216 

Optic nerve, 226 

Organs, 4, 10; of circulation, 134; 
of digestion, 98; of excretion, 
187; of feeling, 223; of hear- 
ing, 232; of movement. 35; of 
respiration, 167; of sight, 225; 
of smell, 238; of temperature- 
sense, 237; of taste, 238; of 
touch, 236, 237; renal, 185, 187 

Osseous or bony skeleton, 14 

Oval foramen, 234 

Oxidation, 82; within the body, 
165 

Pain, 223, 236 
Palate, 100 
Pallor, 63 
Pancreas, 117 



Papillae of dermis, 63, 237; of 

tongue, 238 
Paralysis, 199, 214 
Patella, 21 
Peas, 87 
Pelvis, 21 
Pericardium, 140 
Periosteum, 26 
Perspiration, 66 
Phalanges, 21 
Pharynx, no 
Physiology, 2, 10 
Plasma of blood, 137; action of 

alcohol on, 161 
Pivot-joints, 37 
Pork, 89 
Potatoes, 87 
Practical hints for teachers, 47, 

121, 148, 175, 189 
Process, spinous, 16; odontoid, 

38 

Pulmonary artery and vein, 141; 

circulation, 144 
Pulse, 145 
Pupil, 227 
Pylorus, 1X2 

Radius, 20, 38 

Rectum, 120 

Reflex movements, 197 

Renal organs, 186, 187, 189; ac- 
tion of alcohol on, 189 

Respiration, 163; hygiene of, 176 

Respiratory organs, 167; action 
of alcohol on, 184 

Rest of brain, 210; of muscles, 
52 

Retina, 227 

Rheumatism, 50 

Ribs, 18; movement in breaili 
ing, 172 

Rice, 87 

Sacrum, 16 
Saliva, 106 
Salt, 85, 86 
Scalds, 76 
Sclerotic, 226 
Scurvy, 88 
Scapula, 20 
Sebaceous glands, 67 



26o 



iMrfEX, 



Secretion, 66; of eyelids, 231; of 
intestines, 116; of kidneys, 185; 
of liver, 116; of pancreas, 117; 
of skin, 66; of stomach, 113 

Semicircular canals, 235 

Semilunar valves, 142 

Sensations, 223 

Sense of hearing, 232; of sight, 
225; of smell, 238; of tempera- 
ture, 237; of touch, 236 

Senses, 223 

Sensory nerve-fibres, 196 

Serum, 138 

Shin-bone, 21 

Short-sight, 229, 231 

Shoulder girdle, 20; blade, 20 

Shower-baths, 74 

Sinews, 40 

Skeleton, 12; bony, 14; of back, 
16; of lower limb, 21; of skull, 
19; of trunk, 18; of upper 
limb, 20; hygiene of, 28; table 
of, 22 

Skin, 59; action of alcohol on, 76; 
hvgiene of, 71 

Skull, T9 

Sleep, 207 

Small intestine, 115,116 

Sneezing, 174, 190, 197 

Soap, 74 

Speech, 170 

Spinal cord, ^95; functions of, 
199; nerves, 195 

Spine, 5, 16 

Spinous process, 16 

Spleen, 8 

Sprains, 48 

Standing, 44 

Stapes, 234 

Starch, 84, 89; action of saliva on, 
107; animal, 132 

Sternum, 18 

Stimulants, 91 

Stirrup-bone, 234 

Stomach, 112; action of alcohol 
on, 130 

St. Vitus* dance, 204 

Suffocation, 163, 177 

Sugar, 84; made from starch, 
104; of milk, 87 

Sutures, 18 

Swallowing, no 



Sweat-glands, 66, 75 
Sympathetic nervous system, 2oo 
Synovial liquid, 36 
Systemic circulation, 144 

Table of skeleton, 22 
Taking cold, 153 
Tarsal bones, 21 
Taste, 238 
Tea, 93 
Tears, 231 

Teeth, 101; hygiene of, 104 
Temperature of the body, 77 
Tendons, 40 
Thigh-bone, 21 
Thoracic duct, 119 
Thorax, 6; injured by tight lac- 
ing, 32 
Tibia, 21 

Tight lacing, 32. 182 
Tissue, 4, 10; connective, 12, 13, 14 
Tobacco, 221 
Tongue, 105 
Tonsils, loi 
Touch, 236 
Trachea, 170 
• Trichinosis, 89 
Tricuspid valve, 142 
Tympanum, 233 

Ulna, 20, 39 
Upper limb, 20 
Urea, 185 
Ureter, 185 
Urethra, 187 
Uvula, loi 

Valves of the heart, 142; of veins, 
156 

Varicose veins, 156 

Veins, 134; hollow, t6i; pulmo- 
nary, 141; varicose, 156; 
valves of, 157; wounds of, 159 

Vegetables, 87 

Venae cavae, 141 

Venous blood, 134 

Ventilation, 180 

Ventral cavity, 5, 10 

Ventricles of heart, 140 

Vertebra, 16; atlas, 38; axis, 38 

Vertebral column, 16 

Vertebrate animals, 8, 10 



INDEX, 



261 



Vestibule, 234 
Villi, 118 

Vitreous humor, 228 
Vocal cords, 169 
Voice, 169 

Voluntary muscles, 42 
Vomer, 22 



Warm baths, 74 
Water, 85 
Whiskey-heart, 162 
Willing, 199 
Windpipe, 6, 170 
Worry, 206 
Wounds, 158 



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